- Remove music dir prefs
+ Add refresh album art option to album list context menu
+ Wire up album view context menu
+ Force an idle after transport commands
+ Add "clear cache" button
The app would crash when connection settings were changed. This
refactors the connection logic to be consistent with the rest of the
mpdclient command structure. This ultimately fixes the bug.
* Use the OperationQueue's `operationCount` function instead of keeping
count ourselves. This is reliable now each command is entirely self
contained.
* Rename `queueCommand` to `enqueueCommand`
* Move the command Enum into its own model file
* Move the `enqueueCommand` function into MPDClient+Command