WIP on SimpleGUI

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11275 b7f1a160-662a-0410-a6d8-bea165342f16
Moved Interactor management from QSofaViewer to SofaGL

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11276 b7f1a160-662a-0410-a6d8-bea165342f16
SofaSimpleGUI: Now allows to select Interactors only.

Use Ctrl-Shift-click in qtSofa.

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11277 b7f1a160-662a-0410-a6d8-bea165342f16
added an option to keep the lookAt point of the camera always fixed (p_fixedLookAtPoint)

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11278 b7f1a160-662a-0410-a6d8-bea165342f16