adding bounded grids, so that they can be limited in their ticking direction via data_min/max and in their transverse direction via transverse_bounds and transverse_mapper.  Also replacing some trait change handlers with the on_trait_change decorator.
adding bounded grids, so that they can be limited in their ticking direction via data_min/max and in their transverse direction via transverse_bounds and transverse_mapper.  Also replacing some trait change handlers with the on_trait_change decorator.

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