add missing event handlers for position, to DataView
add missing event handlers for position, to DataView

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