Merging this now since it's basically functional and we're about to split the repo.

Conflicts:
	.travis.yml

Resolved to remote version.

Conflicts:
	.travis.yml
	dune/stuff/test/grid_provider_cube.cc
	dune/stuff/test/grid_provider_dgf.cc
	dune/stuff/test/grid_provider_gmsh.cc

Resolved grid_provider files to local (deleted).
Resolved travis.yml to local except that it includes the new licence header now.

# Please enter a commit message to explain why this merge is necessary,
# especially if it merges an updated upstream into a topic branch.
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# Lines starting with '#' will be ignored, and an empty message aborts
# the commit.