OSX: Completed Library Browser contextual menu.

- Added missing outlets/actions for the Library Browser contextual menu
- Added new actions in ILibraryBrowserView and implemented methods in
LibraryBrowserPresenter for the features accessible through the
contextual menu (Add to playlist, Remove from library, Delete from hard
disk).
OSX: Completed Marker Details.

- Added OnPunchInMarkerDetails action in IMarkerDetailsView and
implemented in MarkerDetailsPresenter.
- Now saving values in Marker Details, every control is working
(changing position, punching in, changing marker details, etc.)
- Reloading markers now keep the previously selected marker in the table
view
- The active marker and marker position are now updated in wave form
view.
OSX: Fixed bugs with markers.

- Markers were not removed when clicking on Remove Marker.
- The active marker flag wasn't reset when clicking on the Back button
of Marker Details.
- The marker wasn't auto scrolling the wave form view when changing the
position with a large zoom value.
OSX: Completed Song Browser contextual menu + bug fix in SongGridViewControl.

- ISongBrowserView/SongBrowserPresenter: Added
OnSongBrowserAddToPlaylist action and added SongBrowserError method.
- Fixed/compeleted Song Browser contextual menu.
- SongGridViewControl: Fixed bug where the mouse on header would not be
invalidated when the mouse was leaving the header from below.
OSX: Several bug fixes in MainWindow + added WheelStepSize to TrackBarControl.

- TrackBarControl: Added WheelStepSize.
- MainWindowController: Removed unused actions/outlets, implemented
missing code in several actions.
iOS: Updated project after changes on other platforms.
WPF + Android: Updated project after changes on other platforms.
Linux: Fixed project after changes on other platforms.