Fix: Show NoMethodError coming from templating engines
Default action available for dynamic routes
LeanMail allows Reply-To header and validates.

- Reply-To header support.
- Email validation for to and reply_to fields (not from, since is not
  expected to be entered by user).
- Should be safe against SMTP header injection.
Version 0.5.1
Hawese payment receipt support
leanweb new: don't require git
leanweb new: don't create public/assets
Fix: Redcarpet content type
Hawese: Handle origin according to new payment API
LeanMail: Fix: Email encoded as UTF-8
debian_setup.sh: Make sure Nginx can read public/
debian_setup.sh:nginx: Don't expire webp nor woff2 files
Locals support on Controller#render_response and #render_with_layout
Fix: bin/leanweb new: Serve dynamic routes first on development.

Try with dynamic routes first, then with static files on PUBLIC_PATH.
bin/leanweb: Sort requirements alphabetically
Fix: require tmpdir on contrib/rack/session/json_file
Improve Debian setup (and don't install emacs-nox)