Add MediaKeyTap to capture media keys

This is resulting in an alarming warning appearing in the console:

```
pid(87021)/euid(501) is calling TIS/TSM in non-main thread environment,
ERROR : This is NOT allowed. Please call TIS/TSM in main thread!!!
```

I've opened an issue on the library GitHub page for now.

Brewfile

@@ -1,2 +1,3 @@
+brew "carthage"
 brew "meson"
 brew "ninja"

Cartfile

@@ -0,0 +1 @@
+github "nhurden/MediaKeyTap"

Cartfile.resolved

@@ -0,0 +1 @@
+github "nhurden/MediaKeyTap" "2.2.0"

Persephone.xcodeproj/project.pbxproj

@@ -24,6 +24,9 @@
 		E41B22C621FB932700D544F6 /* MPDClient.swift in Sources */ = {isa = PBXBuildFile; fileRef = E41B22C521FB932700D544F6 /* MPDClient.swift */; };
 		E41EA46C221636AF0068EF46 /* PreferencesViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = E41EA46B221636AF0068EF46 /* PreferencesViewController.swift */; };
 		E41EA46F221715910068EF46 /* Preferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = E41EA46E221715910068EF46 /* Preferences.swift */; };
+		E421AC9D221F7333008B2449 /* MediaKeyTap.framework.dSYM in CopyFiles */ = {isa = PBXBuildFile; fileRef = E421AC9C221F7333008B2449 /* MediaKeyTap.framework.dSYM */; };
+		E421ACA3221F73C4008B2449 /* MediaKeyTap.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = E421ACA1221F73B8008B2449 /* MediaKeyTap.framework */; };
+		E421ACA4221F73C4008B2449 /* MediaKeyTap.framework in Embed Libraries */ = {isa = PBXBuildFile; fileRef = E421ACA1221F73B8008B2449 /* MediaKeyTap.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		E42A8F3B22176D6400A13ED9 /* LICENSE.md in Resources */ = {isa = PBXBuildFile; fileRef = E42A8F3922176D6400A13ED9 /* LICENSE.md */; };
 		E42A8F3C22176D6400A13ED9 /* README.md in Resources */ = {isa = PBXBuildFile; fileRef = E42A8F3A22176D6400A13ED9 /* README.md */; };
 		E465049A21E94DF500A70F4C /* WindowController.swift in Sources */ = {isa = PBXBuildFile; fileRef = E465049921E94DF500A70F4C /* WindowController.swift */; };
@@ -62,10 +65,21 @@
 			dstSubfolderSpec = 10;
 			files = (
 				E41B22C121FB6C3300D544F6 /* libmpdclient.2.dylib in Embed Libraries */,
+				E421ACA4221F73C4008B2449 /* MediaKeyTap.framework in Embed Libraries */,
 			);
 			name = "Embed Libraries";
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		E421AC9B221F7319008B2449 /* CopyFiles */ = {
+			isa = PBXCopyFilesBuildPhase;
+			buildActionMask = 2147483647;
+			dstPath = "";
+			dstSubfolderSpec = 16;
+			files = (
+				E421AC9D221F7333008B2449 /* MediaKeyTap.framework.dSYM in CopyFiles */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
@@ -128,6 +142,8 @@
 		E41B22EB21FB966C00D544F6 /* playlist.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = playlist.h; sourceTree = "<group>"; };
 		E41EA46B221636AF0068EF46 /* PreferencesViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesViewController.swift; sourceTree = "<group>"; };
 		E41EA46E221715910068EF46 /* Preferences.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Preferences.swift; sourceTree = "<group>"; };
+		E421AC9C221F7333008B2449 /* MediaKeyTap.framework.dSYM */ = {isa = PBXFileReference; lastKnownFileType = wrapper.dsym; name = MediaKeyTap.framework.dSYM; path = Carthage/Build/Mac/MediaKeyTap.framework.dSYM; sourceTree = "<group>"; };
+		E421ACA1221F73B8008B2449 /* MediaKeyTap.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = MediaKeyTap.framework; path = Carthage/Build/Mac/MediaKeyTap.framework; sourceTree = "<group>"; };
 		E42A8F3922176D6400A13ED9 /* LICENSE.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; path = LICENSE.md; sourceTree = "<group>"; };
 		E42A8F3A22176D6400A13ED9 /* README.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; path = README.md; sourceTree = "<group>"; };
 		E465049921E94DF500A70F4C /* WindowController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WindowController.swift; sourceTree = "<group>"; };
@@ -147,6 +163,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				E41B22C021FB6BBA00D544F6 /* libmpdclient.2.dylib in Frameworks */,
+				E421ACA3221F73C4008B2449 /* MediaKeyTap.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -170,6 +187,7 @@
 		E407860F2110CE6E006887B1 = {
 			isa = PBXGroup;
 			children = (
+				E421AC9C221F7333008B2449 /* MediaKeyTap.framework.dSYM */,
 				E407861A2110CE6E006887B1 /* Persephone */,
 				E407862D2110CE70006887B1 /* PersephoneTests */,
 				E40786382110CE70006887B1 /* PersephoneUITests */,
@@ -264,6 +282,7 @@
 		E41B22BE21FB6B3300D544F6 /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				E421ACA1221F73B8008B2449 /* MediaKeyTap.framework */,
 				E41B22BF21FB6BBA00D544F6 /* libmpdclient.2.dylib */,
 			);
 			name = Frameworks;
@@ -390,6 +409,7 @@
 				E40786152110CE6E006887B1 /* Frameworks */,
 				E40786162110CE6E006887B1 /* Resources */,
 				E41B22C221FB6C3300D544F6 /* Embed Libraries */,
+				E421AC9B221F7319008B2449 /* CopyFiles */,
 			);
 			buildRules = (
 			);
@@ -708,6 +728,10 @@
 				CODE_SIGN_STYLE = Manual;
 				COMBINE_HIDPI_IMAGES = YES;
 				DEVELOPMENT_TEAM = BDEE7ZBFZ3;
+				FRAMEWORK_SEARCH_PATHS = (
+					"$(inherited)",
+					"$(PROJECT_DIR)/Carthage/Build/Mac",
+				);
 				INFOPLIST_FILE = Persephone/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
@@ -735,6 +759,10 @@
 				CODE_SIGN_STYLE = Manual;
 				COMBINE_HIDPI_IMAGES = YES;
 				DEVELOPMENT_TEAM = BDEE7ZBFZ3;
+				FRAMEWORK_SEARCH_PATHS = (
+					"$(inherited)",
+					"$(PROJECT_DIR)/Carthage/Build/Mac",
+				);
 				INFOPLIST_FILE = Persephone/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",

Persephone/AppDelegate.swift

@@ -7,10 +7,12 @@
 //
 
 import Cocoa
+import MediaKeyTap
 
 @NSApplicationMain
-class AppDelegate: NSObject, NSApplicationDelegate {
+class AppDelegate: NSObject, NSApplicationDelegate, MediaKeyTapDelegate {
   var preferences = Preferences()
+  var mediaKeyTap: MediaKeyTap?
 
   static let mpdClient = MPDClient(
     withDelegate: NotificationsController()
@@ -21,6 +23,9 @@ class AppDelegate: NSObject, NSApplicationDelegate {
 
     preferences.addObserver(self, forKeyPath: "mpdHost")
     preferences.addObserver(self, forKeyPath: "mpdPort")
+
+    mediaKeyTap = MediaKeyTap(delegate: self)
+    mediaKeyTap?.start()
   }
 
   func applicationWillTerminate(_ aNotification: Notification) {
@@ -42,6 +47,17 @@ class AppDelegate: NSObject, NSApplicationDelegate {
     }
   }
 
+  func handle(mediaKey: MediaKey, event: KeyEvent) {
+    switch mediaKey {
+    case .playPause:
+      AppDelegate.mpdClient.playPause()
+    case .next, .fastForward:
+      AppDelegate.mpdClient.nextTrack()
+    case .previous, .rewind:
+      AppDelegate.mpdClient.prevTrack()
+    }
+  }
+
   func connect() {
     AppDelegate.mpdClient.connect(
       host: preferences.mpdHostOrDefault,

bin/setup

@@ -2,6 +2,8 @@
 
 git submodule update --init
 
+carthage update
+
 cd libmpdclient && \
   meson . output && \
   ninja -C output