add contrasthigh gtk-3 theme and caja improvement gtk-2 for some themes

1. add the caja gtk-2 improvement for the rest of the themes.
2. add contrasthigh gtk-3 theme adapted from gnome-theme-standards
3. add gtk-3 theme support and enable compile of gtk.gresource.xml for gtk-3 themes in configure.ac .

Stefano, i give you access for have a look to configure.ac before merging.