Examine mode transformation matrices of viewarea reworked

Hi,

"_transMat" and "_rotMat" matrices were replaced by single transfromation matrix named "_relMat" that is relative to current viewpoint. "_movement" vector is not needed any more as all the navigation moves are done in local space of current viewpoint.

I have done some interactive tests by myself and haven't found anything suspicious. But it is not a proof for saying that there are no bugs. I haven't tested OnMoveView() method at all as multi-touch navigation does not work on my tablet device for some reason.

There are new methods for navigation, namely:

orbitV(),
orbitH(),
pan(),
zoom(),
rotateV(),
rotateH().

rotateV() and rotateH() methods are not called at the moment, but I added them into pull-request because I think that rotation around avatar up vector should be also possible in examine mode (it could be done with mouse drag when ctrl pressed).

Hope there are no bugs and this is useful.