DOC+BF - docstring rewrite + doctest fixup
DOC+BF - docstring rewrite + doctest fixup

The matlab file generation doctest was testing the directory name as
well as the filename, leading to errors on Mac (they like '-' in their
temporary file directories).

Reformatting docstrings.

nipy/nireg,nipy/nipy-labs,nipy/nipy-labs,arokem/nipy,nipy/nireg,alexis-roche/nireg,arokem/nipy,alexis-roche/niseg,bthirion/nipy,arokem/nipy,bthirion/nipy,alexis-roche/register,alexis-roche/nipy,alexis-roche/register,arokem/nipy,bthirion/nipy,alexis-roche/register,alexis-roche/nireg,bthirion/nipy,alexis-roche/niseg,alexis-roche/nipy,alexis-roche/nipy,alexis-roche/nipy