Fill in a lot of missed cases (mostly just messages)

- Increase strength of slayer weapons that weren't in the original BoE by making sure that each race applies some multiplier to the ability strength
- Messages for every occasional status effect, both negative and positive. If charm/forcecage, ignore.
- Fix weapon poison not being applied
- Forcecage supported for damaging terrain (in town only, of course) and "affect status" items
- Weapon poison supported for "affect status" items; it differs from "poison weapon" items in that it honours the magic use type and doesn't risk messing up (like the Envenom spell)
- Show error messages when encountering an unimplemented spell or special node
- Fix missing handling of NPCs appearing after town dies when loading a saved town

src/scenedit/scen.core.cpp

@@ -1040,6 +1040,7 @@ static bool edit_monst_abil_detail(cDialog& me, std::string hit, cMonster& monst
 			case eMonstAbilTemplate::BREATH_DARKNESS:
 				param = get_monst_abil_num("Breath weapon strength:", 0, 4, me);
 				break;
+			default: break; // None of the other templates take parameters
 		}
 		// Protect from overwriting an existing ability.
 		auto save_abils = monst.abil;