* gimp_splash.ppm: added the splash-screen image drawn
by Jens Lauterbacher to the distribution
* app/appenv.h
* app/app_procs.c
* app/main.c: added the splash-image to the startup-window;
new command-line options: --no-splash, --no-splash-image
* ps_menurc: changed to reflect changes to the
menu-structure