Now diablo.h is treated in the same way as all other header files of
Source, as it only contains the declarations of global variables and
functions of diablo.cpp.
Besides consistency, this also enables mods to include diablo.h just
like any other header file without having to include every header file
(and without having to include C++ specific aspects of the now all.h).
* Clean up DeleteMonster
* AddMonster
* Clean up NewMonsterAnim
* Clean up M_Ranged, M_Talker and M_GetDir
* Clean up M_StartDelay
* Clean up M_StartSpStand
* Clean M_StartSpStand
* Add enum to monster Anim