* pixmaps/*.png: Move images to ui/ directory.  This makes for
a more streamlined directory structure, and besides "pixmaps" was
a horrible name anyway.
* pixmaps: Remove directory.
* Makefile.am: Accomodate for the change from "pixmaps" to "ui".
As a side effect, the .dirstamp hack for ui/ is also no longer
necessary, as the ui/stockimages.h rule already covers this.
* src/main.cc: Change stockimages.h #include accordingly.

svn path=/trunk/; revision=577