Push

Clojush minor enhancements/fixes, intertwined spirals.

Available as usual from: https://github.com/lspector/Clojush

20101204: - Added pushgp-map, which allows pushgp calls on maps of arguments,
            and a demonstration of its use in argmap_regression.clj.
          - Added :gen-class and -main definition (thanks Kyle Harrington).
          - Fixed eval-push termination to return :abnormal for exceeding
            time-limit (thanks Kyle Harrington).
20101205: - Added modified version of Kyle's version of the intertwined
            spirals problem.
          - Minor changes to this README.