ENH: check data type in microphone.readWavFile
RF: microphone move getOnsetMarker out of class AdvAudioCapture

- allow calls without needing an audio capture instance
RF: prefer #!/usr/bin/env python2

- my editor removed some trailing whitespace as well; the only substantive changes are to the #! line
Merge pull request #520 from jeremygray/master

use 'python2'; microphone minor RF