clean_threat_table() removed; handle_regen() removed; handle_respawning() removed; update_player_view() removed (cont)

ss::ErrorID::ERROR_UNKNOWN_PACKET removed; ss::MapInfo merged into
ss::Map; world_server renamed to universe_server; load_plugin() added;
load_plugins() added; unload_plugin() added; unload_plugins() added;
ss::TextureManager added; get_plugins() added; ss::Texture added;
ss::TPETile added; ss::StarbornTile added; ai plugin added; projectiles
plugin added; regen plugin added; respawn plugin added; update_view
plugin added; clean_threat plugin added