Set Vary: Origin on CORS requests

The Access-Control-Allow-Origin header is set depending on the request's Origin
header. Although most requests also send Cache-Control headers with no-cache,
the OPTIONS requests for CORS pre-flight requests do set cache headers.

See http://www.w3.org/TR/cors/#resource-implementation
Renamed license file to standard LICENSE
Added example for hapi server framework.
Merge pull request #134 from mbrevoort/master

Renamed license file to standard LICENSE
Fix license references
Merge pull request #139 from Oobert/master

Added example for hapi server framework.
Merge pull request #130 from davidben/master

Set Vary: Origin on CORS requests
Release 0.3.9
Set heartbeat timer if needed, even if send_buffer

Fixes #143
Add CORS headers to eventsource
Fix usage of Access-Control-Allow-Credentials
Remove charset from even source. Spec says it is always utf-8.
Merge pull request #158 from jcheng5/master

Set heartbeat timer if needed, even if send_buffer is not empty
Merge pull request #168 from sockjs/cors-eventsource

Add CORS headers to eventsource
Fix #96 remove rbytes
Fix #83 Update prefix docs
Fix #163 add protection from SWF JSONP exploit
Fix #104 get rid of unused parameters
Fix #106 Update sockjs CDN urls
Upgrade deps