Fixed segfault after double-run-stop
Fixed nullifying light sensor segfault;
Fixed 2D motors leaks;
Some attempts to speed up restarting 2D model
Some changelog additions;
Fixed stupid warning
Fixed enourmous slowing when restarting interpreter
Merge branch 'master' of github.com:qreal/qreal into robots
Robots translated to qt5;
New qextserialport version added
Added spiky modern style fix
Merge pull request #664 from dvvrd/robots

QReal:Robots Qt5