fix tox.ini: use Pillow with necessary fixes; use latest django releases; add djnago 1.4 to tests; add pypy and python 3.2; remove django1.2 support.

django 1.2 is removed from tox.ini because tests already fail under django 1.2 (see #201).
Pillow currently points to my repo; this should be changed when necessary fixes are merged.
pypy must be >= pypy 2.0 beta1 (pypy 1.9 doesn't work).

All tests pass on my machine.