ENH: Improved bundle creation on the Mac at make install time. Built-in plugins, Qt Assistant and python shell should now work 'out of the box' with the Mac bundle after a make install. Caveat: need to use CMake 2.6.2 or later which includes BundleUtilities.cmake. Further caveat: works with Unix Makefiles for now, maybe with Xcode later. Recommendation: Use 'DESTDIR=blah make install' from the build tree and see unix-y stuff go to blah/usr/local and the bundle go to blah/Applications.