annoying dependency on javaws.jar (which no longer even includes JarDiff, now
that lives in $JAVA_HOME/samples/jnlp/servlet/jardiff.jar). We had already
forked JarDiffPatcher, so this completes the circle. Now I can also directly
fix some of the annoying JarDiff bugs we were working around, which I'll do at
some point.
os.name. If no architecture is specified, all architectures match, which
preserves the existing behavior.
Restructured things along the way to be more amenable to unit testing, and
added some unit tests.
Michael Bayne