NF starting working on adding color FA in the dti.py
Added a function to compute the RGB/ColorFA and a test.
Added 2D and 1D test cases
Added minors corrections to colorfa.
Added a test to check if fa and evecs shape are matching and if the two last
dimensions of evecs are (3,3).
Now following pep-8 regarding lower case variables names.
Merge pull request #128 from samuelstjean/colorfa

Colorfa