Trac #18418: Clean Hyperbolicity Module

Improve the hyperbolicity module by performing the following cleanings:

 * rename "cuts" -> "CCL", "cuts+" -> "CCL+" or "CCL+FA";
 * set "CCL+" as default (it is faster);
 * include approximation algorithms using "cuts+" (already included, but
an error is raised at the moment);
 * put counting sort of pairs in a separate routine;
 * use uint_32 and not uint_16 for pairs (graphs can have more than
`2^16` vertices);
 * rename algorithm "basic+" to "basic".

URL: http://trac.sagemath.org/18418
Reported by: borassi
Ticket author(s): Michele Borassi
Reviewer(s): David Coudert