remove unnecessary imports, remove cache suffix setting, ensure matplotlib uses numpy.
remove unnecessary imports, remove cache suffix setting, ensure matplotlib uses numpy.

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