Theme updates:

- Section title images in the tunnel manager + presentational tweaks
  - Separation of server/client tunnels for consistency in iframed/separate view
- More responsive layout tweaks specifically for narrow viewports
  - Lessens UI breakage, particularly for languages with long translated strings
    (ru, de etc)
- Susimail light theme enhancements
- Incremental theme tweaks including Arabic (light/dark) & Chinese
  (classic/dark/midnight)
- Fixed placement of "Welcome to I2P" h2 on /home for new users
- Fixed conflicting .home#home div on homepage (now #homepanel)
- Fixed double select dropdown icon in Internet Explorer/MS Edge
- Addressed minor rendering issues in IE 11 and MS Edge