Add Control Pushbuttons for adjusting the file bpm by small amounts.

file_bpm_up and file_bpm_down.  This will be great for small bpm tweaks
when the detection engine is off by a bit.
Add beats_translate _left and _right.
Use the correct method to adjust the overall bpm
Unify naming a little more
more unification
change naming again: beats_translate_earlier / beats_translate_later
Merge pull request #325 from ywwg/filebpm_tweak

Add Control Pushbuttons for adjusting the file bpm by small amounts.