[ADD] doc's readme

* also only enable linkcode if Sphinx >= 1.2
* fix html inline roles?
[ADD] support for a version switcher in odoo theme thing

needs beauty input
[FIX] base: remove test_ir_model, which causes bugs

The test in test_ir_model creates a custom model.  This causes a full reload of
the registry, which recursively installs the required modules while 'base' is
being tested.  As a side effect, it commits stuff from the database, so that
the effects of test_ir_model are actually not rolled back.
Merge branch '8.0' of https://github.com/odoo/odoo into 8.0-linux64