Fix switch warnings (#4013)

* Fix switch warnings
  * Fix a variety of -Wswitch and -Wswitch-enum warnings
  * Remove unneeded -Wno-error flags

* Reorganise some eMonsterType switches
  * Alpha sort eMonsterType cases in WriteMobMetadata
    and in cNBTChunkSerializer::AddMonsterEntity
  * List all mob types in protocol 1.12 and NBTChunkSerializer

* cStructGenTrees::GetNumTrees: remove switch default

* cWSSAnvil::LoadOldMinecartFromNBT: Log unhandled minecart type

src/Mobs/Monster.cpp

@@ -1034,10 +1034,12 @@ cMonster::eFamily cMonster::FamilyFromType(eMonsterType a_Type)
 		case mtZombie:       return mfHostile;
 		case mtZombiePigman: return mfHostile;
 
-		case mtInvalidType:  break;
+		default:
+		{
+			ASSERT(!"Unhandled mob type");
+			return mfUnhandled;
+		}
 	}
-	ASSERT(!"Unhandled mob type");
-	return mfUnhandled;
 }
 
 
@@ -1053,10 +1055,12 @@ int cMonster::GetSpawnDelay(cMonster::eFamily a_MobFamily)
 		case mfAmbient:   return 40;
 		case mfWater:     return 400;
 		case mfNoSpawn:   return -1;
-		case mfUnhandled: break;
+		default:
+		{
+			ASSERT(!"Unhandled mob family");
+			return -1;
+		}
 	}
-	ASSERT(!"Unhandled mob family");
-	return -1;
 }