Refactored the fuzzy time helper

Felt a bit more explicit this way, but I was merely playing around with the code ;)
Swap out admin behavior with locksmith behavior

Data should be migrated before this is pulled in, otherwise nobody will
be able to unlock assignments.
Reorder static pages. Fixes #436.
use do … end instead of staches
use include method
Rename requires in ruby tests
Determine nav tabs based on active trails. Fixes #432.
created better examples for anagram
updated clojure tests with real words
fixed archaic spelling of pigeon
Updated elixir anagram test with real words
updated anagram test in go
updated anagram in js to use real words
updated anagram to use real words in python
Filter assignments in sidebar

For the most part users only have access to exercises they've completed.

This still doesn't remove exercises that don't have any pending
submissions.
Merge pull request #437 from markijbema/better-anagram-examples

created better examples for anagram
Fix smoke test
Show nits_before_but_not_on_this_iteration on Featured
Merge pull request #439 from markijbema/refactor-fuzzy-time

Refactored the fuzzy time helper
Merge pull request #438 from markijbema/small-refactorings

Small refactorings