OSX: Bug fixes in wave form related controls + added menu options.

- WaveFormControl: Fixed bugs when changing display type.
- WaveFormScrollView: Added more options to the contextual menu (reset
zoom, choose display type). Added a few prototypes to change the zoom
behavior depending on the mouse location. Not satisfied with the result
for now.
- WaveFormCacheService: Changed signature of GetTiles method to reduce
the number of parameters. Now generating correct tiles depending on
display type.