Python safety

[lowtorola]

Now that we will be accepting python submissions, we need to be sure that all of our infrastructure is safe from potentially-malicious python code. This safety testing should include detailed analysis of the following:

• our compilation runners cannot be affected by the python code (this should be safe :))
• our execute runners are not susceptible to injection/attack by python code (here, a dev should try to actually inject/malign our infra)
• our current usage of clamAV can catch bad python code (we should check that it catches reference suspicious code that should be retrievable from the internet)