Some inconsistent code migration
Merge branch 'master' of github.com:qreal/qreal into 2d-model-code-improvement
Accomplished moving large pieces of code from D2ModelWidget to D2ModelScene
Fixed world loading issues.
Fixed incorrect robot`s position resetting when clearing.
Merge branch 'master' of github.com:qreal/qreal into 2d-model-code-improvement
Fixed display toggling button`s horizontal expansion
Fixed possibility to drag robot out of the scene rect
Autoexpanding made a bit smarter: now it takes into account just robot item
Fixed incorrect sensor`s dragging direction after adding colliding wall
Fixed segfault when drawing an item from the sensor above the robot
- 2d model scene is aligned to top left corner of the view
- some small styleguide fixes
examples need to be updated according to new scene position