Need a universal binary of the JavaApplicationStub for Spark.

Java applications on OSX are launched by a small native program called JavaApplicationStub. Jarbundler grabs the JavaApplicationStub included with the OS, but on PPC Macs that's a PPC-only binary. This causes OSX to use the Rosetta PPC emulation system to start JavaApplicationStub up, which is probably slowing our launch time a little on Intel Macs.