fix get_query_set deprecationwarnings in django master
run tests against django 1.6.x branch. stop running them against django master on python 2.6
Fix compatibility with Python 2.6.1 (Snow Leopard)

This workarounds a bug in Python 2.6.1 that has been fixed in later versions. Since this version is the default one in Snow Leopard system, it makes sense to add a simple, non-invasive workaround.

The bug is that **kwargs wouldn't work with unicode literals, and it's been fixed in Python 2.6.5:
http://bugs.python.org/issue4978
fix usage of python_2_unicode_compatible decorator
remove dodgy commit_unless_managed from _move_node, how the heck did that get there?
also use transaction.atomic() in docstrings for things.
Fix modelform test error wiht django 1.7/master