The `categories.description` column is not modified as "not null", so it is possible for the description to be nil. This changes the code not call html_safe on nil.
- add microdata based on schema.org
- add breadcrumb on the top of topic
- add navigations link on the bottom of every pages
- add category description on the category list
- removes an (n+1) query for user data
- supports the preload store for the data to avoid a second request
- fix a bug where uncategorizes was reporting (0, 0, 0) for topics by week, month, year
Ryan Mulligan
Benjamin Elijah Griffin
Arpit Jalan
Régis Hanol
Robin Ward
Neil Lalonde
Erick Guan
Sam
Jeff Atwood