made SoQt::mainLoop() release the global interpreter lock so that pivy can be used interactively from within the python interpreter without the need to use PyQt and qApp.exec_loop() as a workaround...
made SoQt::mainLoop() release the global interpreter lock so that pivy
can be used interactively from within the python interpreter without the
need to use PyQt and qApp.exec_loop() as a workaround...

looooo/pivy,looooo/pivy,looooo/pivy