Adding OGProjectionNOX<Scalar>::project_global(SpaceSharedPtr<Scalar> space, MeshFunctionSharedPtr<Scalar> source_meshfn, Scalar* target_vec, ...)

 - needed by
	OGProjectionNOX<Scalar>::project_global(SpaceSharedPtr<Scalar> space, MeshFunctionSharedPtr<Scalar> source_sln, MeshFunctionSharedPtr<Scalar> target_sln, ...)
   and
	OGProjectionNOX<Scalar>::project_global(Hermes::vector<SpaceSharedPtr<Scalar> > spaces, Hermes::vector<MeshFunction<Scalar>* > source_meshfns, Scalar* target_vec, ...)

Also updating some comments in ogprojection_nox.h
Allowing calc_abs_errors and calc_norms to work with Filters.

So far only for Filters wrapped by MeshFunctionSharedPtr; same approach can be used for versions taking direct MeshFunction pointers.