SFRotation<-SFMatrix4F renamed to rotate<-matrix
Adding funtion to extract translation from matrix
Bit of clean up.

Deleting older unused code and decorating a bit.
Adding Screen and Head physical devices.

Other than the 2d-mouse we are now adding Head (tracking) and
Screen (display) device classes and corresponding run methods.

This will enable us to do some VR work with cl-3d. The default single
screen configuration defaults to something that can be used on a deskop
with a 45 degree FOV. This can remain as it is for a desktop.

Head is currently identiry but will enable use to do some head tracked
VR once connected to a tracking device.
Adding more utilities.

A bunch of stuff were added and removed here. The utilities have gotten
better but more may be needed. This file gets filled up as an when
needed by implementation.
Adding Navigation routine

The navigation routine takes a viewport and navigation matrix and
formulates a navigation technique. The navigation routine is by no means
complete and more work may be needed here. However what we currently
have is workable.
Adding VR mathematics for Projection and ModelView

VR typically takes into account the coordinates of the tracked head
with respect to a base and screen coordinates wrt the same base. This
helps in aligning the virtual work with the real world.

CAVE's TiledWall and other VR setups can be used or atleast we have the
capability to use them.
Merge branch '2d-mouse-pan-zoom'