* Modules/Debuggers/ProjectCenter/GNUmakefile: Add images
to makefile.
* Modules/Debuggers/ProjectCenter/PCDebugger.m: Add up and down
methods to implement this behaviour.
* Modules/Debuggers/ProjectCenter/Resources/down_button.png
* Modules/Debuggers/ProjectCenter/Resources/up_button.png:
Images for the up/down buttons.
git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/apps/projectcenter/trunk@27459 72102866-910b-0410-8b05-ffd578937521