Autogenerate dependency graphs, documentation with travis

[spitters]

This can be done as in the
https://github.com/HoTT/HoTT

@Zimmi48 , does the coq-community has standard template for this?
It makes sense to role out this tools uniformly

[Zimmi48]

Indeed, it would.
I'm only getting back into looking at the CI question and preparing a template for this, so this could be a follow-up.