_Also_:
* Use `mapnik::freetype_engine::register_fonts` in `gen_tile.cpp` rather than recursing manually
* Available since `Mapnik` v2 which is no longer supported
* Add tests for `ModTileCacheExtendedHostName` and expired tileOld/TileVeryOld
* Add tests for `ModTileEnableTileThrottling`/`ModTileEnableTileThrottlingXForward`