void World::PlayerCommand(std::string command, const std::vector<std::string>& arguments, Command_Source* from)
{
std::unique_ptr<System_Command_Source> system_source;
if (!from)
{
system_source.reset(new System_Command_Source(this));
from = system_source.get();
}
PlayerCommands::Handle(util::lowercase(command), arguments, from);
}