Add test for image header roundtrip.  Updated header values should be saved.
Add test for image header roundtrip.  Updated header values should be saved.
arokem/nipy,alexis-roche/niseg,alexis-roche/nipy,nipy/nipy-labs,alexis-roche/nipy,bthirion/nipy,alexis-roche/nipy,bthirion/nipy,alexis-roche/nireg,alexis-roche/niseg,arokem/nipy,alexis-roche/register,arokem/nipy,alexis-roche/nireg,nipy/nireg,bthirion/nipy,nipy/nipy-labs,alexis-roche/register,arokem/nipy,alexis-roche/nipy,bthirion/nipy,alexis-roche/register,nipy/nireg