Remove Lunatic-related code

This removes almost anything related to Lunatic, not just LunaCON. It may remove a bit more than desired, e.g., functions that can be used as possible hooks (I believe that this was one purpose of LUNATIC_EXTERN, now replaced with static anywhere).

Some bits like the optional fix for software rendering of walls with non-POT tile heights remain, albeit they're still compile-time disabled.

As previously written, I still know that Philipp Kutin was spending a lot of time on this.