Improve usability of command line QML profiler

The command line qml profiler won't quit if the application being profiled spontaneously quits but will instead give a confusing error message.

In order to be used by automated tasks it should

1. have an option not to process user commands while running
2. expect the application to exit by itself
3. properly process the "Complete" message to figure out if all the data has been received
4. quit after the application has quit and all data has been processed.
5. Use the double dash argument stlye as most Qt utilities do, e.g. "--help"
6. Accept a specific file name and path where the trace should be saved. Rigt now it just save to some cryptic date-coded filename in the current path.