[tox] use master URL for yams repository No need to clone from review. This should help get consistent results.

[pylint] Avoid invalid-name on schema relation class names

[pylint] more work on the pylint support * uniformize usage of ClassDef and simplify related import * don't insert in the ast a python function but an astroid representation of that function * ignore __pkginfo__ file * drop attr-rgx, variable-rgx and argument-rgx, put the name in good-names instead * drop additional-builtins * add cell_call to the list of methods for which we don't want 'abstract-method'