Open the first non-flag argument if one is given

Fixes up simplebrowser to act similarly

Change-Id: I40270a0f7bc06ce52117f23f7ccbdd743d3d97f6
Reviewed-by: Peter Varga <pvarga@inf.u-szeged.hu>
Reviewed-by: Kai Koehne <kai.koehne@qt.io>