added a doc string to schema_gen.py and a note in models.py

refs SPOT-624
fixed the tests so that they'll pass regardless of local_settings

refs SPOT-624

tests were failing because some of the were uw specific. factored
them out so that the uw specific ones were in the uw_tests and
now the general ones are in the regular test directory
Merge branch 'jswan2' into working
SPOT-596: Made default datetime aware and set tz to GMT