Jetpack with Capistrano and external jar dependencies

Note: this is our first time using Jetty.  These fixes allowed us to use jetpack with capistrano and other jar dependencies.  If not suitable/correct pls let us know!

1. Removes RAILS_ENV requirement in jetty-init if app_type is not rails.
1. Uses @path_to_project for the bundler gem.  Given we are setting this anyway and thus have the fullpath, it seemed easier than try to make sure $PATH was setup correctly.
1. Adds jar_includes to the jetpack.yml file to allow extra jar files to be included.  These are inserted into the extraClasspath of the jetty.xml after the jruby jar files.