Displaying splash on application startup is added to GUI/Session package. In start *.py scripts the following chages were made:
1) added "SPLASH" parameter to SalomeApp.xml resource file and its handling in launchConfigureParser
2) moved section of conversion of "GUI", "CPP", "PY", "SUPERV" parameters (and new "SPLASH") from unused SessionLoader to SessionServer, these parameter are now passed to SessionServer on launch and they are handled there.
3) start of SessionServer is moved to the very beginning of startSalome (to display splash).
