add positionChanged singal to allow drawing trajectory
add possibility to recalculate mass based on fixture densities
allow change collision filtering  without fixture re-creation
expose angularVelocity to QML
add missing QuickItem::geometryChanged() call
re-create fixture shape in the case of position changes
- allow change circular fixture position using x/y properties
- make initial fixture position to be center of the parent (independently on the radius)
fix access violation during disposal of nested bodies
android/gcc-4.8 compilation fix: add missing includes