added conditional block to handle case where the data array is 1 dimensional
added conditional block to handle case where the data array is 1 dimensional

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