Optimize query string parsing

 *  Parsing code was moved to cowlib: cowboy_qs:parse_qs/1
 *  A function was added to build query strings: cowboy_qs:qs/1
 *  Also added cowboy_qs:urlencode/1 and cowboy_qsurldecode/1
Add link to the repository of elixir Cowboy examples
Add a workaround to disable chunked transfer-encoding

This is an undocumented workaround to disable chunks when using HTTP/1.1.
It can be used when the client advertises itself as HTTP/1.1 despite not
understanding the chunked transfer-encoding.

Usage can be found looking at the test for it. When activated, Cowboy
will still advertise itself as HTTP/1.1, but will send the body the same
way it would if it was HTTP/1.0.
Merge branch 'adrianroe-streaming-http1.1-compat'
Clarify error msg for route lacking starting slash
Merge branch 'dsucher-better-routes-without-start-slash-error'
Use try/catch instead of catch

Thanks Richard Carlsson for the remainder.
Remove an unnecessary clause in cowboy_req:body/2
Properly send 201 on PUT requests when resource didn't exist

Regardless of whether a location header has been set, as explained
in the HTTP RFC.
Update erlang.mk
Update Ranch to 0.9.0
Update ROADMAP
Add documentation for cowboy_spdy
Update CHANGELOG
Update AUTHORS
Update Cowboy to 0.9.0
Merge tag '0.9.0' into heroku_unstable