Grading: do not set wallclock_timeout when timeout is 0 (closes: #175).
StupidSandbox: correctly honour wallclock_timeout == None.
Set requests dependency to v1.1
Fix ProxyService

It stopped retrying to contact dead RWSs when the flow of new data in
queue stopped.
Fixes to a couple of recent commits
Add EventSource WSGI handler
Port RWS to gevent
Change a couple of titles in CWS

Make the task name more prominent.
Add a backdoor.
Add OII 2013 to testimonials list
Fix a couple of commands in the documentation

The dash changes the working directory to the home of the postgres user,
avoiding some "could not change directory" errors.
Use only new-style classes.
Changed JSONDecodeError to ValueError.

It is needed after moving from simplejson to json.
Adapt some pydoc to the correct format for raises.
Changed class to type when appropriate in the pydoc.
Timestamps are now in datetime.
Digests are really unicode strings.
Added logging explanation to two exceptions.

First is "wrong connection string", second is "service not specified
in conf". First still has several occurrence - we fixed only the case
in which the offer accepts a contest id.
.