Make [*time_area] Lua API functions take a single time area id

This means the Lua code implementing the WML tags are now solely
responsible for parsing the comma-separated id list. It just so happens
that I added code for that without realizing that I was duplicating
existing functionality on the C++ side.

As a result:
 * wesnoth.add_time_area and wesnoth.remove_time_area can operate on
   time area ids that contain commas (if someone feels this is needed
   for some weird reason)
 * [time_area] no longer warns about adding time areas with commas in
   their ids (actually adding the first id of the list instead)
 * [time_area] remove=yes and [remove_time_area] still handle
   comma-separated lists of ids, in the Lua side instead of C++.

This makes the Lua API for this consistent with [event]/[remove_event].

Since the Lua API functions in question are undocumented at this moment,
it's unlikely this impacts anyone, really.

changelog

@@ -64,6 +64,9 @@ Version 1.13.1+dev:
    * Add helper.get_nth_child
    * Add helper.child_count
    * Add helper.child_array
+   * wesnoth.remove_time_area no longer takes a comma-separated list of time
+     area ids.
+   * wesnoth.add_time_area no longer warns about commas in time area ids
  * Music and sound effects:
    * New sounds: dwarf hit and die, ink, mud fist and glob.
  * Terrains:
@@ -154,8 +157,8 @@ Version 1.13.1+dev:
    * Add new syntax for [option], similar to the new difficulty syntax
    * Add [test_condition] ActionWML that tells why a conditional failed (for debugging)
    * Add [remove_time_area] WML tag which takes a comma-separated list of time
-     area ids, and make [time_area] id= accept a comma-separated list when
-     using remove=yes as well.
+     area ids.
+   * [time_area] no longer warns about commas in ids when not using remove=yes.
  * Editor:
    * Added Category field and color sliders to the Edit Label panel.
  * Miscellaneous and bug fixes:

src/scripting/game_lua_kernel.cpp

@@ -4073,35 +4073,26 @@ int game_lua_kernel::intf_add_time_area(lua_State * L)
 	log_scope("time_area");
 
 	vconfig cfg(luaW_checkvconfig(L, 1));
-	std::string id = cfg["id"];
-
-	if(id.find(',') != std::string::npos) {
-		id = utils::split(id,',',utils::STRIP_SPACES | utils::REMOVE_EMPTY).front();
-		ERR_LUA << "multiple ids for inserting a new time_area; will use only the first" << std::endl;
-	}
+	const std::string id = cfg["id"];
 
 	std::set<map_location> locs;
 	const terrain_filter filter(cfg, &game_state_);
 	filter.get_locations(locs, true);
 	config parsed_cfg = cfg.get_parsed_config();
 	tod_man().add_time_area(id, locs, parsed_cfg);
-	LOG_LUA << "event WML inserted time_area '" << id << "'\n";
+	LOG_LUA << "Lua inserted time_area '" << id << "'\n";
 	return 0;
 }
 
 /// Removing new time_areas dynamically with Standard Location Filters.
 int game_lua_kernel::intf_remove_time_area(lua_State * L)
 {
-	log_scope("time_area");
+	log_scope("remove_time_area");
 
-	const char * ids = luaL_checkstring(L, 1);
+	const char * id = luaL_checkstring(L, 1);
+	tod_man().remove_time_area(id);
+	LOG_LUA << "Lua removed time_area '" << id << "'\n";
 
-	const std::vector<std::string> id_list =
-		utils::split(ids, ',', utils::STRIP_SPACES | utils::REMOVE_EMPTY);
-	BOOST_FOREACH(const std::string& id, id_list) {
-		tod_man().remove_time_area(id);
-		LOG_LUA << "event WML removed time_area '" << id << "'\n";
-	}
 	return 0;
 }