Add more functions that deal with the infrastructure for solving local problems on patches around cells.

The functions DoFTools::count_dofs_on_patch() and DoFTools::map_global_dofs_to_patch_indices() help set up linear systems on patches. This is joint work with Arezou Ghesmati.
Merge pull request #37 from bangerth/add-patch-generators

Infrastructure functions for local problems on patches

The functions DoFTools::count_dofs_on_patch() and
DoFTools::map_global_dofs_to_patch_indices() help set up
linear systems on patches.
This is joint work with Arezou Ghesmati.