JRobin 1.5.8 Speedup

One month ago I created a patch for JRobin. And today I've submitted it to project's page on sourceforge. For graphs with CDEFs this patch speeds up graph creation by the factor of 10 and at least by the factor of 1.5 for graphs without CDEFs. In addition it makes possible to draw arbitrary graphic on top of created graph and use full-featured java code instead of CDEFs (extends Plottable class).

The patch