SofaSimpleGUI: added an external project.

Temporarily discarded the Qt subproject, and replaced it with a (zipped) external project.
This can be used as a starting point to embed Sofa in an pre-existing Qt application.
The project file is not yet general, however.

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11099 b7f1a160-662a-0410-a6d8-bea165342f16
added a release mode to SofaQtExternal

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11100 b7f1a160-662a-0410-a6d8-bea165342f16
FIX the project file of the Qt Sofa external project.

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11101 b7f1a160-662a-0410-a6d8-bea165342f16
???

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@11102 b7f1a160-662a-0410-a6d8-bea165342f16