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

When OS unders 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 at the same time, though OS will restart the service later when has enough memory, it doesn`t guarantee to response to Camera event any longer (when photo taken, no uploading task invoked). This PR is targeted to handle this problem, but not finished coding yet.

Also, Changed icons in order to launch a new version.