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: Starting to implement the SFM.
RF: Make sklearn an optional package.
NF: First pass at fitting the thing.
Starting to work on signal prediction.
Abstract out the design matrix construction. Predict.
BF: Make it work with different in/out situations.

On to test that it does something sensible (signal-wise).
TST + BF: More testing, more fixes.
TST: More tests.
Handle errors in the ODF estimation.
When signal is zero, set params to all-zeros, not nans.
TST: update the tests.