Added a first draft for a hashconsed term, not tested!
This is experimental and will obviously change a lot. It's badly designed with
many redunctant code, but it's only a proof of concept. For now, the idea is to
use it with the de Buijn index to avoid the alpha conversion.
Refactoring
Top-down rewriting

Now rewriting replaces terms top-down  (not only first level)
Some improvements
Merge branch 'master' of github.com:ptal/nominal-workbench into hashcons
Draft for de Bruijn indexes
Added .merlin for those interested
add two strategies : bottom-up + top-bottom, add a param to rewrite_rec (the strategy)
Added some cases
Merge branch 'master' of github.com:ptal/nominal-workbench into hashcons
Added a pretty printer for hashconsed terms
+ tests in a subdir of system
Début de travail sur stratégies
add fixes for pretty (a pretty pretty printer)
Started adding the new keywords and directives
Merge branch 'master' of https://github.com/ptal/nominal-workbench
delete local test file from ocp
Merge branch 'master' of https://github.com/ptal/nominal-workbench
Modified hashconsing to use referencing instead of de Bruijn
Added unit tests for hashconsing, still more to test but promising
Merge branch 'master' of github.com:ptal/nominal-workbench into hashcons