BF - set default smooth in shm to .006
BF - fix scaling for Csa Model
NF - added gfa attribute to SphHarmFit class
DOC - clarify docs for SphHarmModel
Merge branch 'shm-small-fixes' of https://github.com/MrBago/dipy into csa_odf_example_test
Merge branch 'fx-assume-normed' of https://github.com/MrBago/dipy into csa_odf_example_test
added a shm_model test. Opdt model still has issues in the SH coefs. Qball and CSA are great