Remove multiple header writes

Contains 2 changes - 
1. Increase ReadTimeout. I believe that some POSTs to the edge are failing because they are large. 
2. We are writing headers multiple times (http://golang.org/pkg/net/http/#ResponseWriter) and as such writing a lot to stdout as go is complaining.

If memory serves, we're currently unable to know how many ReadTimeout's take place because the stdlib ServeMux handles all of that logic. Perhaps we should do the work to be able to record these states. Rhys' chitin library (internal to twitch) seems to have some hooks for this, perhaps good inspiration.