Avoid django DST error: bug 1092647

Use tz-aware datetime in query to avoid automatic conversion by
django.utils.timezone.make_aware, which will throw an error during DST
change, because Zen. https://code.djangoproject.com/ticket/22598
Merge pull request #2438 from jgmize/future-dst

Avoid django DST error: bug 1092647
[fix bug 1092851] Firefox OS: Wrong link to Czech T-Mobile shop
Merge pull request #2439 from alexgibson/bug-1092851-firefox-os-wrong-link-czech

[fix bug 1092851] Firefox OS: Wrong link to Czech T-Mobile shop
Add content for /firefox/tiles page
Bug 1059518
Merge pull request #2413 from sgarrity/bug-1059518-tiles

Add content for /firefox/tiles page