[TIMOB-15653] MobileWeb: Mozilla forces pre-flight of request with OPTIONS method, causing failure of XMLHttpRequest

Mozilla browsers (Firefox and Firefox OS) are handling XMLHttpRequests differently from other browsers tested as working (Safari, Chrome). XMLHttpRequests processed via Firefox are sent as a preflighted request with a method of OPTIONS. This causes a failed response from the server in use for the particular project I am working on. CORS has been setup on the server providing the data feed. I have been able to get a valid response by commenting out lines 12-23 of SDK/mobileweb/titanium/Ti/Network/HTTPClient.js (this._handles = [...]), forcing a plain/text Content-Type, and removing all custom headers from the request. However this results in no onLoad and therefore can only be observed via a web debugging proxy. I have discovered this while developing an app for the new Firefox OS, so a fix for this would be pertinent in making Titanium a viable choice for developers looking to build apps for Firefox OS.