BUG: Move the main in ortho_slicer to a demo function, and fix it to actually work.
BUG: Move the main in ortho_slicer to a demo function, and fix it to
actually work.

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