Add GM_xmlhttpReq grant & patched FF 29 "insecurity" bug

[Mod][Fix]: As of greasemonkey 2, permissions much have 
explict @grant's for each GM API used. As such, added 
@grant GM_xmlhttpRequest and unsafeWindow.
[Fix]:  FF 29 introduced a bug where localStorage would
 cause a "The operation is insecure." for localStorage. 
This was fixed by setting it to unsafeWindow.localStorage.