Do not remove duplicated Set-Cookie entries

This commit closes #195, closes #199, closes #246.
Return "400 Bad Request" instead of crashing process on incorrect queries like /%qq
Merge branch 'master' of git://github.com/josevalim/cowboy
Fix dispatch documentation with regards to the <<"*">> path
Merge branch '400_Bad_Request' of git://github.com/blinkov/cowboy
Check for errors when calling Transport:send in the websocket protocol

In some situations, the underlying socket might become "half-open" in
which case the websocket will stay in a waiting state indefinitely. The
detection of this state requires checking for errors when calling send.
Do not try to keep-alive when using HTTP/1.0
Cosmetic changes to various documentation files
Merge branch 'fix/websocket-check-error-on-send' of git://github.com/tillitech/cowboy
Fixed onrequest path-related issue
Merge branch 'onrequest' of git://github.com/saleyn/cowboy
Fix a test that worked intermittently
url and host_url may return undefined

this can happen when the request parsing fails and onresponse
needs the url, its perfectly possible that the url has not
yet been defined
charsets_provided in rest module to return [binary()]
Merge branch 'master' of git://github.com/chancila/cowboy
Clarify error reports indicating they come from Cowboy
Update the cowboy_websocket_handler specs

We can send many payloads at once.
static: Allow passing the mimetype fun as a {M, F} tuple
Add a better error message when user callbacks are not exported
Return a 400 error if the Accept header was incorrect