Missing product image in equation after reset-all (Sandwiches screen)

[ycarpenterphet]

URL: http://www.colorado.edu/physics/phet/dev/html/reactants-products-and-leftovers/1.0.0-dev.13/reactants-products-and-leftovers_en.html Version: 1.0.0-dev.13 Issue occurs in OSX 10.9.5/Chrome and iPad2/iOS7 (and likely elsewhere as well)

If the reset-all button is pressed on the Sandwiches screen, the image of the product for both Cheese and Meat & Cheese sandwich equations disappears. The correct calculations are still being performed (i.e. correct numbers are displayed for products and leftovers), but no images are drawn of the product (in the equation, the 'after reaction' box, or in the legend below the reaction box).

e.g.

[pixelzoom]

Initial icon for all 3 sandwich equations was initially empty, to handle the 'custom' sandwich. But the 2 static equations need a valid initial icon, in order for 'Reset All' to work properly. Fixed in above commit, and in http://www.colorado.edu/physics/phet/dev/html/reactants-products-and-leftovers/1.0.0-dev.14/reactants-products-and-leftovers_en.html

Reassigning to @ycarpenterphet for verification. If this looks ok, please close.

[ycarpenterphet]

Looks good, closing.