refactoring segmentation into its own module
history stacking
recurrence plotting
updated version number in dev branch
implemented structure features
Merge branch 'master' into develop

Conflicts:
	librosa/__init__.py
segment => agglomerative, asymmetric recurrence
helper function for magnitude/phase separation
added a unit test for magphase
load now handles offset and truncation
added a pad option to recurrence features
adding metric option to recurrence function
added rbf support for recurrence plots
Merge branch 'master' into develop
mattmcvicar: added support for loudness-based chroma (in feature.py) and pretrained chord recognition (in the new chords.py)
Added simple chord estimation parameters in minmaj_params.txt
Adding peak pick function
Adding onset function.  Default params should be optimized.  Moved onset_strength to new onset submodule.
Formatting
fixed a strange ligature bug