Added LICENCE (the pure GPL text copied verbatim from gnu.org) and README.

Started to add a NetworkX plot in plots.py

system/plots.py

@@ -498,6 +498,28 @@ class ScatterPlot(Plot):
         self.ax.plot(xdata_new,ydata_new,'or')
         self.canvas.draw()
 
+class NetworkPlot(Plot):
+    def __init__(self, dataset, name='Network Plot'):
+        Plot.__init__(self)
+
+        fig = Figure(figsize=(5,4), dpi=72)
+        self.ax = ax = fig.add_subplot(111)
+
+        self.canvas = FigureCanvas(fig)
+        self.add(self.canvas)
+        self.canvas.show()
+
+        self._toolbar = NavToolbar(self.canvas, None)
+        self._toolbar.set_property('show-arrow', False)
+        self._toolbar.set_select_callback(self.rectangle_select_callback)
+        
+    def get_toolbar(self):
+        return self._toolbar
+
+    def selection_changed(self, selection):
+        return None
+    
+
 # Create a view-changed signal that should be emitted every time
 # the active view changes.
 gobject.signal_new('view-changed', MainView, gobject.SIGNAL_RUN_LAST,