added test that fails when run in conjunction with OneToManyFilteringTest
Adapted querytime propagation - seems to work now (output still very verbose): "Don't assign query time to a field, it's static!"
Cleaned up unnecessary verbosity
Added backwards compatibility for Django 1.6
Added support for Django 1.6 & Python 3 (meh...)
Consolidated backwards compatibility handling
Added tests for more DB backends
clean up a couple of leftover references to AsOfInfo
check if existing cached instance matches as_of before fetching from db
tests: Use a consistent object description for test models
tests: add a test for a two-hop select_related
Merge pull request #31 from swisscom/select-related-tested

Fixed the still failing query time propagation.

Conditional statements in JOINs were added with wrong aliases in the case data was prefetched. This is done when using the 'select_related' method on a Django QuerySet.
The result was a wrong set of results returned from the DB (since the SQL statement was wrong, obviously).