We should try not to bundle "compiled" and source versions of
third-party code. In this case, minification should be done on all
Javascript in Mahara and then cached. jQuery is far from being the
only JS file that would benefit from being compressed.

Change-Id: I65d5b63fc80258bfa4e80ca6fb0578870e61664a
Signed-off-by: Francois Marier <francois@catalyst.net.nz>