Improve pagination

* Override bootstrap's @paginationActiveBackground to be darker gray
* Improve `includes/pagination.html` so we can use it site-wide
* Add pagination to Question list
* Add pagination to Followers/Following lists
* Use sitewide pagination template for list of users
* Use sitewide pagination template for feed aggregator
* Use sitewide pagination template for project list
* Add username and count of answers to Question list