Fixed bugs in wave form related classes.

- WaveFormControl: Introduced new look for scrollbar without waveform.
- TileHelper - Fixed bugs in end dirty tile calculation.
- WaveFormEngineService: Added routine to pickup tiles from lower zooms,
still buggy. Set new tile size to 250 which is much faster than before.
- WaveFormRenderingService: Fixed bug where the bitmap would not
sometimes be filled because of fractions in startLine/endLine.