ENH: allow SLR to have input previous transformations
TEST: reduced number of iterations for faster execution time
Report on coverage for old scipy.
BF - make examples was confusing files with similar names, fixed
Merge pull request #481 from MrBago/bf_make_examples

BF - make examples was confusing files with similar names, fixed
Merge pull request #479 from arokem/travis-old-scipy

Report on coverage for old scipy.
DOC: corrected typo
TEST: make sure SLR(x0='rigid') == SLR(x0=np.zeros(6))
Merge pull request #480 from Garyfallidis/enhance_slr_multi

Enhance SLR to allow for series of registrations
NF: unique rows of an array.
NF: Added a crutch function. This will need to be removed later on.

And replaced with `move_streamlines`, but I am defering that until I get a
sense of what is happening here.
NF: Added a first-pass implementation of LiFE.
RF: Thinking about simplifying this.

Maybe use dipy.sims.voxel directly?
WIP: Completed the mapping function voxel2fiber, inclduing test.
Matrix allocation more-or-less working.
WIP: Still working out how to create this model.
NF: Added Sparse SGD algorithm for solution of the LiFE equations.
TST + BF: Make sure that input to np.gradient is an array.
RF: Move down the fit function.
RF: docs