bug #4716 :  Now, when a space manager or an administator is in the process of creating an application, both the existance and the visibility property of this application is checked. In the case the application to instanciate doesn't exist or isn't visible, an error page is then displayed to the user
bug #4717 :  Restrict the instantiation of applications in the user personal space to only the ones visible to this particular workspace.
bug #4717 :  Send an error when an unexisting application instantiation is asked