Added mass-weighted COM removal.
Revised docstring in COM weighting.
Fix cffi docstrings
Merge pull request #185 from rmcgibbo/cffidocstring

Fix cffi docstrings
Merge pull request #183 from kyleabeauchamp/mass_weighted_center

Added mass-weighted COM removal.
Added save() for legacy HDF
Minor docstring update for compat
Added pre-loading of top in multi-traj loading.
Added comment of kwarg processing.
Merge pull request #190 from kyleabeauchamp/load_speedup

Load speedup
Use iteritems from six for py3k
Merge pull request #187 from kyleabeauchamp/save_legacy_hdf

Added save() for legacy HDF
Added load and save for legacy HDF
Warn on saving to legacy HDF
Added test for save_legacy_hdf and added to __all__ in trajectory.py
Merge pull request #192 from kyleabeauchamp/default_compatibility

Default compatibility
Change everything to LGPL
typo fix in two .c files
s/Foobar/MDTraj/g
Remove references to Foobar