Get TB building against JRuby 1.7.5
Use JRuby 1.7.5 instead of 1.7.5.dev
Remove dead code related to building on JRuby < 1.7
Get TB build working under JRuby 1.7.5 in 1.8 mode
Get Rails 2.3.x apps working with JRuby 1.7.5

This may not work for all Rails 2.3.x apps, but it works for our
integration test apps.
Get windows .bat files generating again under JRuby 1.7.5