automatically enable use of evolution mask in GRHydro when CarpetEvolutionMask is active

[Roland Haas]

I attach a patch to provide an "auto" option to use_evolution_mask that will enable the mask if thorn CarpetEvolutionMask is active. As already stated, I don't really prefer this option since it seems like too much cleverness in code which is bound to eventually bite us. I will only apply this last patch if requested. The others will be applied on Sunday (I have no idea how to nicely implement the comments for 0012 since Fortran does not allow per-file local function definitions).

Keyword: GRHydro

[Frank Löffler]

Please apply - after the depending patch has been applied first of course (the one introducing the parameter in the first place)

[Roland Haas]

Applied as rev 469 of GRHydro.