RemoveProduct Bug Fix 2, and other things

The remove product function definitely removes the correct product this
time.
The new product button doesn't disable if you try to create a product
without a name, all buttons disable during the computer's turn, the
current player's products move to the front during their turn, and the
regress/remove button doesn't arbitrarily disable anymore.
Also the popup overlay and window have higher z-indexes in order to stay
above the products at all times.