Trackers to send data to Datahem collectors.
Fix to clean up pixel and beacon trackers
Added conditions to downgrade gracefully if user agent doesn't support sendbeacon even if it says support it supports sendBeacon. Also when beacon chosen as tracker method, always send first hit as xmlhttp POST to enable CORS in some browsers
Wrapped GA sendHitTask in try-catch to allow sending hits to datahem collector even if GA limits are exceeded.
Added a filename (collect.gif) to img get request path
This release use the cloud endpoint collector as the receiving endpoint of tracker requests. The payload is encapsulated as an json object with the key payload if sent as navigator.beacon or ajax POST.