move entity related content from g_local.h into g_entities.h
add include guards to g_local, bg_local, bg_public and unvanquished.h
add #define for player entity classname
remove unused include
replace the literal *BUILTIN* layout names with a #define
merge gentities target_ent and enemy consistently into 'target'
rename notify function pointer to notifyHandler
refactor "targeted" to "tracker" to also clarify the meaning of the 5th version of a "target"-ish named variable
refactor spinup time into the activeAt delay time