Redesign Firefox Sync page for Bug 1046251
- Conditional contents depending on browser type/version
- New content/design only applies to en-US until other locales opt-in
Add Spice phone to Fx OS pages. Bug 1056903.

- Add Tamil screenshots to /firefox/os/.
- Improve selector used for en-US/India content on /firefox/os/.
- Switch HTML comments to Jinja comments on devices page.
Merge branch 'bug-997577-legal-notices' into demo2-bug-997577-legal-notices-and-bug-1046251-sync-updates
Merge branch 'bug-1046251-sync-updates' into demo2-bug-997577-legal-notices-and-bug-1046251-sync-updates