REV/DOC KIT head shapes:  drop support for pickled head shapes
TEST
TEST coreg:  fit_matched_points
ENH coreg:  make fit_ functions more similar

- add out='trans' option to fit_point_cloud
- RF:  transformation parameter to transformation matrix conversion
ENH kit2fiff:  automatically decimate head shape points for files with too many points
TEST coreg:  fit_point_cloud