NF - add gfa attribute to spherical harmonic fits
TST - added test for gfa of sh models
RF - rename _gfa_sh and make it private
Merge pull request #268 from MrBago/add_gfa_shmfit

Add gfa shmfit
NF: robustifying median_otsu for dwi data
Added new tiny volume in dipy/data for tests
NF: now the median_otsu function can have as input non S0 slices and tests with small real dataset were added
Updated with Ariel's suggestions
Replaced with vol_idx as discovered by Matthieu
Tiny commit to wake up Travis
Merge pull request #271 from Garyfallidis/median_otsu_robust

Increased the power of median_otsu masking by allowing to include non S0 volumes to the mask.
Fixed typos + autopep8
Changed rodriguez to rodrigues
Merge pull request #273 from samuelstjean/typos

Fixed typos + autopep8