Better exports of hints in Graph.v
Factor out instances for Compcert types from Graph.v.
Fix _CoqProject
Add a tentative merlin project file.

It does not work properly I will investigate why another time.
New combinatorize.

It should be more resilient to large terms than the previous one. But it doesn't really improve the situation for the terms I previously had.

At the very least it is a bit more modular than the previous version which can encourage more experimenting.
Prelimininary adaptations of Summary.v to the nominal architecture.
Fix Makefile.
Ocaml 4's cmt files in .gitignore.