Remove some old unused mara zap code. Ignore an entity's constantLight field if it is not ET_MOVER or ET_MODELDOOR as these are the only types that the server-side code creates a constant light in. For the mara, constantLight is used to store entity nums which erroneously caused a dynamic light to be created on each zap.
Merge pull request #345 from slipher/zapzap

Fix mara zap dynamic light bug (?)