Patch Set 9: I would prefer that you didn't submit this

This really still isn't ready.  I took Matthias' native work and hacked it apart, and put it back together a little.  In JNI land we now fill out the LStat object directly, rather than allocating an intermediate int[].  We also cache handles to the LStat object type, but we should also do this for the common error class types to make constructing the exception quicker.

Build works under Maven 2.2.1 on Mac OS X.  I'll have to test on Linux tomorrow.  Copying the generated libjgit_native.jnilib into the target plugin is a bit messy.  I really don't know how the JGit feature will work for a P2 build when we need to generate it on different platforms and merge the results, since some plugins aren't buildable on every platform.

The Mac OS X build now requires the Java SDK, which is part of Xcode and is in /Developer. But that shouldn't be a huge problem, you probably need Xcode to get gcc anyway.