GitLab

programs: fixed typing related to exceptions which cannot be raised, or possibly raised but no occuring in post (by the way: how should we issue warning in Why 3?)

- programs: labelled annotations and labelled WPs
- ide: color labels in source view

programs: complete rewrite of the type-checker in progress (in particular, types dterm and dfmla have been moved to Denv, together with some functions); make does not compile whyml anymore; make bench will stop at the first program test; with my apologies if I messed up somewhere...

programs: more efficient access to pre-defined symbols; typing is now state-less (to be re-entrant, if necessary)