updated Fader to use setHintText
enables setting of the display text.
Merge pull request #1434 from curlymorphic/fader

updated Fader to use setHintText
Bitcrush: small improvement, also add some stuff to math & constants
Constants:
- calculate all in long double so as to improve the accuracy of our pre-calculated constants
- add some possibly useful constants: reciprocal of pi, square of pi, and reciprocal of e
Math:
- new math convenience functions: absMax, absMin
Merge pull request #1439 from diizy/master

Bitcrush: small improvement, also add some stuff to math & constants
Update FxMixer.cpp

prevent double adding of jobs
Merge pull request #1440 from LMMS/stable-1.1

Update FxMixer.cpp
More fixes (Bitcrush, Linkwitz-Riley filter)
Merge pull request #1441 from diizy/master

More fixes (Bitcrush, Linkwitz-Riley filter)
Merge pull request #1 from LMMS/master

rebase from master