Add tests for the Qt UI.

Make sure the Qt UI quits if WIRESHARK_QUIT_AFTER_CAPTURE is set. Make
sure Bourne shell scripts (*.sh) have UNIX/POSIX line endings. Reduce
some time values so that the tests run faster.

Change-Id: I81df7c6f72d7d807d1856863cbea1bb6326ca711
Reviewed-on: https://code.wireshark.org/review/4407
Tested-by: Gerald Combs <gerald@wireshark.org>
Reviewed-by: Gerald Combs <gerald@wireshark.org>