More GUI changes. Changed the names of some variables in UIKnob to better reflect what they are.
Merge branch 'master' of https://github.com/SeanROlszewski/iOS-Additive-Synthesizer

# By Sean Olszewski
# Via Sean Olszewski
* 'master' of https://github.com/SeanROlszewski/iOS-Additive-Synthesizer:
  Update README.md