pkg: rewrote the install process We now have a single extension. - enable is dropped - a setup.py is added - the doc is updated to reflect this

evolve: add the odiff alias

[pkg] Add a setup.py

Ignore build directory

update documentation

doc: some terms update

rename `stabilize` to `evolve` stabilize keep being valide but as Matt still like "Changeset Evolution" as a name evolve make more sense. Stabilize is a bit too tight to unstable too.

merge evolve and obsolete

sort import

Fix mercurial version check