fixing DataRange2D to listen for changes on its contained DataRange1D
fixing DataRange2D to listen for changes on its contained DataRange1D

ContinuumIO/chaco,burnpanck/chaco,ContinuumIO/chaco,tommy-u/chaco,ContinuumIO/chaco,tommy-u/chaco,tommy-u/chaco,burnpanck/chaco,ContinuumIO/chaco,burnpanck/chaco