* configure.in: corrected test for libXmu for some systems; added test for
difftime
* app/main.c: use glib ATEXIT macro
* app/text_tool.c: applied gimp-stric-980321-0 (text preview refresh)
* plug-ins/script-fu/script-fu-console.c: don't need to init gtkpreview stuff,
since we don't use them
* plug-ins/script-fu/*: many portability fixes
* plug-ins/pnm/pnm.c: sprintf portability patch
* plug-ins now #define RAND_MAX if needed
* plug-ins/sparkle/sparkle.c: applied gimp-joke-980322-1
-Yosh
* 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
