Update the SimpleCache implementation and docs to be up-to-date with Django 1.3+.
pin python3-digest to allow its beta package to install without passing the --pre flag to pip >= 1.4
Merge pull request #1047 from damoti/master

assertHttpAccepted produces better error message
Documented that tests can be run with tox

Also noted that tests may not *always* pass with development versions
of Django.

Closes #1048 and closes #857.
Removed py26-dev tox environment

This was missed in commit 4320db4ac, I believe.

Closes #312.
flakes
Raise BadRequest if JSON decode fails (closes #1053)

Previously anything which caused an error in the underlying
`simplejson.loads` call was not caught. Now ValueErrors are converted
into BadRequest so they'll generate an HTTP 400
Merge pull request #1036 from lukeman/pin-python3-digest

pin python3-digest to latest version in requirements
Merge pull request #1052 from daftshady/dev

More Pythonic None equality check in cache.set
Merge pull request #1001 from mattdeboard/simplecache

Update SimpleCache implementation and docs for Django 1.3+