Made gr3_createsurfacemesh independent from gr

gr3_createsurfacemesh is now independent from the state of gr by default.
Removed the surface parameter from gr3_createsurfacemesh.
Changed the GR3_SURFACE_* constants.
Changed gr3_surface accordingly.

Change-Id: I707dac4346fa50c46454cae1e2414b25442d1f0c
Reviewed-on: https://iffwww.iff.kfa-juelich.de/review/23
Reviewed-by: Josef Heinen <j.heinen@fz-juelich.de>