Changed ES5 getter to be a regular function.  This improved the performance on iPad significantly, though I'm not entirely sure why.  See https://github.com/phetsims/neuron/issues/55.
Changed ES5 getter to be a regular function.  This improved the performance on iPad significantly, though I'm not entirely sure why.  See https://github.com/phetsims/neuron/issues/55.

phetsims/griddle,phetsims/griddle,phetsims/griddle