Update app to use Python 2.7

Note that this doesn't fully work yet.
Replace simplejson with json
Add a basic document on testing
Set threadsafe to true
Revert "Set threadsafe to true"

Let's wait until we can get the other stuff working first.

This reverts commit a80a3315a40e051e16458a437aa8d0e398cc0583.
Enable threadsafe
Add copy of stdlib rlcompleter.py, with "import __main__" commented out

This doesn't work correctly in the app engine, but we don't use __main__
anyway.
Enable the external library numpy

This will let people import numpy in the SymPy Live shell.
Add matplotlib
Clean up JavaScript & jQuery 1.9 compatibility
Make sure docs link renders
Add back prototype for DS support
Merge pull request #1 from lidavidm/python2.7

Fixes
Implement cache-busting scheme

Conflicts:
	shell.py
Merge pull request #2 from lidavidm/p2.7

Implement cache-busting scheme
Merge pull request #65 from asmeurer/python2.7

Update app to use Python 2.7