Bug 1000937 - Disable caching of static resources

Verified by:

	~/Code/fxos-certsuite % curl -I http://localhost:6666/app.html
	HTTP/1.1 200 OK
	Content-Length: 1091
	Accept-Ranges: bytes
	Server: TornadoServer/3.2
	Last-Modified: Wed, 23 Apr 2014 11:47:27 GMT
	Etag: "e8b8d419e5697dd40415636a38fdfc38"
	Cache-Control: no-cache
	Date: Tue, 29 Apr 2014 11:21:49 GMT
	Content-Type: text/html