adds zero crossing rate
fixes merge conflicts, adds to the readme
spectral rolloff
spectral rolloff
fixes merge conflict
Merge pull request #39 from hughrawlinson/zcr

Zcr
fixes merge conflicts
fixes merge conflict
tweaked readme and fixed index conflicts
fixes another merge conflict
Merge pull request #41 from hughrawlinson/spectralRolloff

Spectral rolloff
fixes merge conflict