fixing bugs related to bpm view - 1. bpm text wasn't being instantiated at start 2. bpm tap regression where bpm was always set to max, got rid of bpm tap button, now can just tap on the bpm view itself, bpm drag only works with up/down scrolling (got rid of right/left scrolling), improved longpress in ClickableBBView by using event handler, added longpress listen to BPM view to bring up a number input to manually enter BPM.  Removing dead ClickableSurfaceView class