DOC: Working on RESTORE example. Enhanced DTI docstring.
WIP
BF: Consider the absolute value of the residuals.
DOC: RESTORE example with data.
BF: This test was bogus.
BF: This ensures the test passes once more.
BF: This goes along with the last commit.
DOC: Example with simulation, instead of data.
BF: Two things related to RESTORE.

1. Weights on the GMM have to be renormalized.
2. Last-pass fitting is done without weighting.

The second point seems particularly important to make this method work.

without weighting.
DOC: keep this around, for a rainy day.
BF: Only iterate once through here. Otherwise, this might be overkill.
DOC: example with actual data.

This seems to work now (!).
DOC: One more pass through the text of this example.
Merge pull request #275 from arokem/restore-example

Restore example