NF: Command line interface to QuickBundles.
BF: Make sure that dipy_quickbundles gets installed.
RF: More fixes.
RF: More work to get it to be compatible with vistasoft conventions.
RF: Improvements: cluster colors, pickle-saving.
BF: Save .trk file header. Don't error every time, when using .trk files.
TST: Testing the QB script.
RF + TST: Use save_pickle and test it.
TST: dipy_quickbundles requires mpl.
TST + RF: Added an option to specify the output path. Added MPL to Travis.
RF: Clean out some cruft.
Also save centroids as output.
refactoring
removed the last dimension reshaping gfa array
BF - zip object to list
RF - minor
fixed typo in comment
RF: Implemented the beginning of a base-class.

Also: converted dti.design_matrix to use gtab as input. This required changes
upstream in predict/adc/tests.
DOC: added a docstring.
WIP: Trying to inherit more models from ReconstModel/ReconstFit