Add Jython or Groovy scripting engine support

Network exploration often requires doing sequences of actions over and over again, for example automatically applying force-directed layout, followed by coloring nodes based on attribute values, filtering of unimportant nodes, changing node size, ... Tools like GUESS (http://graphexploration.cond.org/) provide an embedded scripting engine like Jython (http://www.jython.org/) or Groovy (http://groovy.codehaus.org/) for these purposes. Basically, these embedded engines make data structures and operations available to the user in a programmatic way. Typically, people can load in a pre-developed script (automation) or type scripting code in an interpreter window (exploration). Supporting Jython and/or Groovy would add significant value to Gephi.