Additional fixes after convo with Cianw:
Additional fixes after convo with Cianw:

* attach near-nullspace to pmat not mat
* fix the fieldsplit case, by passing in the right operators
to the setup_ksp_from_options after attaching a nullspace if specified
* new create_null_space_from_options_scalar that handles the scalar
case and now also checks the test_null_space option which was previously
ignored for that case. The existing vector case is renamend
create_null_space_from_options -> create_null_space_from_options_vector

rjferrier/fluidity,jjo31/ATHAM-Fluidity,iakovos-panourgias/fluidity,jjo31/ATHAM-Fluidity,rjferrier/fluidity,jrper/fluidity,jrper/fluidity,rjferrier/fluidity,jrper/fluidity,rjferrier/fluidity,iakovos-panourgias/fluidity,iakovos-panourgias/fluidity,jrper/fluidity,iakovos-panourgias/fluidity,jrper/fluidity,jjo31/ATHAM-Fluidity,jjo31/ATHAM-Fluidity,iakovos-panourgias/fluidity,jjo31/ATHAM-Fluidity,rjferrier/fluidity