v2.2.0 Test build

What's new in this version

Contains the following fixes and improvements to AudioSample and SoundFile:

• implement correct calculation of current playback position() (see #28)

• stop jump() from unintentionally spawning new sample players

• add informative warning messages when calling read()/write() on stereo samples

• add cueFrame(), jumpFrame() and positionFrame() methods

• add playFor() methods

• add playFrame() methods