Support files

It is mildly annoying that it's not clear what support files (video, 
audio, image, etc.) files exist, especially because of the current 
system where tests are copied around, so relative urls to files outside 
of a single submission are likely to break.

It would be nice to fix this in two ways:

1) Create a repository like "support" that could be put at the top 
level, much like resources, allowing links like /support/images/pass.png 
to work.

2) Stop moving files around in repositories and track code review other 
than through position in the filesystem hierarchy.