Added new actions and methods to ILoopsView.

- All actions that could be done in ILoopDetailsView can now be done in
ILoopsView.
- Updated OSX and iOS projects.
Refactoring of scrubbing speed support in TrackBarControl.

- Moved some of the code into ScrubbingSpeedHelper.
- The ScrubbingSpeed class is no longer part of TrackBarControl.
- Added IScrubbingSpeedSupport interface to standardize scrubbing speed
use.
- Prepared WaveFormControl to support scrubbing speed change.
- Added prototype for scrubbing speed panel on OSX.
iOS: Fixed empty cells on iOS 8.

- The cells in MobileLibraryBrowser were empty and were no longer
showing text on iOS 8.