Move emailtemplate, fix testdata

fixes #333, fixes #389.

this PR combines the two changes to add one less test_data.json.gz to the repo.

the emailtemplate move migration itself works, but things like database flushing might not work like expected afterwards. it looks like django/south don't handle moving models between apps well.

see the commit message for changes int he test_data. using nonnatural keys gained 10s, not loading the fixture twice gained another 30s. loaddata now runs in 50s instead of 90s.i think that's enough for now for #333.