[phenixbb] warning: do not upgrade Mac OS yet!

There is some kind of strange issue with wxPython on the new Mac OS ("Mavericks"), which for at least the 1.8.4 version prevents Phenix application windows (but not the main GUI) from opening. It is also printing out an extraordinary number of warning messages about fonts to the console. I'm hoping there is a simple solution (which seems likely, since 1.8.2 is mostly okay despite using the same version of wxPython), but until we figure out what is causing this, I recommend leaving your Macs unmolested if you want to use the Phenix GUI. Updates to follow if-and-when I fix this. thanks, Nat