optimize camera upload service to keep itself running and responding as long as possible

When OS under memory pressure, it will kill the service to save CPUs and resources for the foreground applications. In this case camera upload service will be killed along the way, though OS will restart the service when has enough memory, it doesn`t guarantee to response Camera event (when photo taken, no uploading task invoked). This RP is targeted to handle this problem, but not finished coding yet.

Also, Changed icons in order to launch a new version.