Camera "shakes" when panning if nearDistance is very small

Open Inventor

At least for certain camera orientations, when nearDistance is very small, e.g. 0.001 or 0.0001, panning left and right in the viewer caused the camera to "shake" up and down while moving. 

Default algorithm relied on inverted matrices and was causing precision issues when changing  OIV_CLIPPING_TOLERANCE to small values (such as 0.00001). We now only compute a world scale Ox vector that is next transformed given camera orientation. The camera is then translated given this vector.