Merge pull request #102 from tamiko/make_icc_happy

Fix test memory_consumption_01 for icc
Move create_union_triangulation() and extract_boundary_mesh().

These functions were previously in GridTools, but conceptually they create
meshes and so should be in GridGenerator. Move them there but leave the
old functions in GridTools with a note that they are now deprecated.

Also structure the documentation of the functions in GridGenerator better.
Merge pull request #103 from bangerth/move-functions

These functions were previously in GridTools, but conceptually they create
meshes and so should be in GridGenerator. Move them there but leave the
old functions in GridTools with a note that they are now deprecated.

Also structure the documentation of the functions in GridGenerator better.
CMake: Remove non-functional code

This actually never worked...
CMake: Remove all "help" targets

It turns out that CMAKE_PROPERTY is too buggy to be useful. We cannot
set property CMP0037 to the old behavior in order to define a custom "help"
target in a macro without a warning. o_O
Merge pull request #104 from tamiko/cmake_fixes

Cmake fixes
intermediate