Remove -Xss argument.

It looks like in #4, someone was under the impression you can pass
arbitrary JVM flags here. This is, in fact, not the case. As a result of
this chage we were getting usage information on the console every time
we tried to invoke yui.
Merge pull request #5 from farmdawgnation/compressor-messer

Compressor Messer: Remove -Xss argument.