EMI: Sprite fixes

This fixes several issues related to sprites in EMI.

For example, the transparency of the coals in wed now matches the original renderer. The candles and the aura effects are drawn in the set gmi. The lights on Stan's house work properly, and Stan himself is also fixed.

Note that the renderer changes are not fully implemented for the TinyGL renderer. Correct alpha blending would be required to bring the TinyGL renderer up to par with the other renderers.