Add the ability for styx to attach CORS headers

This change adds a new routing rule that handles CORS headers.  It also incorporates a new version of http-proxy which doesn't have a resource leak bug in it.  Yay?

Lastly, I pushed up dependency versions and switched everything to use amoeba instead of the local files.

@kentquirk @jh-bate If you have a chance please look this over.  I have to deploy it to devel in order to get blip to work against it, so I will most likely push it through in the morning if you guys don't have a chance tonight.