RF: remove roi module pending rewrite
RF: remove roi module pending rewrite

The ROI module needs some work and does not have tests. It's in a
prominent place, and Bertrand's ROI modules are a better option at the
moment.  Remove for now, pending proper refactor.

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