Part 1 of a major reorganization of content. Moving "instant" to "builder"
and setting up "builder" more like the "gui" part as a package. Moving the
Rappture::object stuff from the builder into the main installation, so it
can be shared by the tester as well. Moving "driver" into gui/scripts
where it belongs. Creating a new "launcher.tcl" script that decides
which of the three parts to launch based on command line options. Still
need to sort out the Makefiles to get this all right...
