Add go-fasthttp 20160617

A fast HTTP implementation for Go.

Currently fasthttp is successfully used by VertaMedia in a production
serving up to 200K rps from more than 1.5M concurrent keep-alive
connections per physical server.

WWW: https://github.com/valyala/fasthttp

• While I'm here:
  • Use DISTVERSIONPREFIX
  • Add LICENSE_FILE
  • Add missing RUN_DEPENDS
  • Remove GH_PROJECT

PR: 217212
Submitted by: Guy Tabrar <guy.tabrar@me.com>