+ Twig: Provide request_path as global variable.
+ comment & @todo for Twig extension
Support more twig function, move function fetcher to new class.
Quick fix for /at/twig form.
+ Support constructive-class as callback for Twig filters.
Convert callbacks for Twig filters to constructive-classes.
Merge pull request #116 from andytruong/cleanup/twig-extension

Cleanup Twig extension