Created flat skin for AIS_Manipulator presentation
Added "-flat" option to vmanipulator command
Added functionality to transform the manipulator depending on the camera rotation.
Added local transformation for Graphic3d_Group.
Added RecomputeTransformation method to PrsMgr_PresentableObject.
When overloading this method, you can set a transformation for an object depending on the rotation of the camera.
v3d/manipulator/flat: test case added
Completed the stop transform action when dragging manipulator with mouse.
Added context redisplay for update of interactive object sensitive areas.
Added test.
