Vanntile/inkscape docking system test
Rebased version of @vanntile 's GSOC work. Also fixed the problem with wrong dialog titles.
For some reason, Prefs and doc properties are unavailable ?
also : two warnings on quit: SPDesktop::setEventContext: No toolname! SPDesktop::getInkscapeWindow: Failed to get window.
Edited by Marc Jeanmougin