phetioFeatured overrides

[arouinfar]

For #296

Opening an issue to track the commits.

[pixelzoom]

I confirmed with @arouinfar that she can commit the overrides.js file without breaking CT, because this sim does not yet have an API file. Ditto for concentration.

[arouinfar]

I've committed a first pass at the phetioFeatured overrides. Next steps are to review in master and cleanup as needed, and then take care of Concentration.

[arouinfar]

I reviewed the phetioFeatured overrides in BLL, found a few elements that slipped through the cracks and addressed in a161d4b. Then, I copied over all of the global and concentrationScreen overrides to Concentration (replacing beersLawLab with concentration), tested locally to make sure I didn't break anything with the replace all method. Everything looked okay, so I went ahead and committed to Concentration. Master looks fine to me, so I'm going to to close.