Added the event for setArmorModel on a Living(Biped)-Entity

Allows custom rendering implementations that are currently only available for playerrendering to be used on biped entities. The patch can be extended to be used for all living enities, but i did not see the need to implement it on a lower level than the biped entity.

I made the implementation of the If-Statement a little bit bigger to stay conform to the implementation that is used for players. If this is not desired I will make it a oneline statement (as that should be possible).