getPan() returns a value between -1 and +1
add comment that explains why setVolume() is called in setPan()
fixes formatting of setVolume() function
Merge pull request #1777 from thiagohersan/bugfix-androidSoundPlayerGetPan

Fixes getPan() in Android SoundPlayer
Merge branch 'develop' of https://github.com/openframeworks/openFrameworks into bugfix-readme.android