Switch return type of _execute/_draw/_delete to be bool by default instead of BOOL

It's not completely consistent, but it seems like the majority used `bool`, and only a handful used `BOOL`. So I switched all of them to `bool` except for 13 TUs that stopped matching when changed like this.

src/d/actor/d_a_obj_eff.cpp

@@ -177,7 +177,7 @@ void daObjEff::Act_c::remove() {
 }
 
 /* 0000126C-00001290       .text _delete__Q28daObjEff5Act_cFv */
-BOOL daObjEff::Act_c::_delete() {
+bool daObjEff::Act_c::_delete() {
     /* Nonmatching */
 }
 
@@ -217,7 +217,7 @@ void daObjEff::Act_c::die() {
 }
 
 /* 0000149C-000014C0       .text _execute__Q28daObjEff5Act_cFv */
-BOOL daObjEff::Act_c::_execute() {
+bool daObjEff::Act_c::_execute() {
     /* Nonmatching */
 }