Test haskell/word-count for prefixed punctuation

This is a failure case I discovered in my own word-count submission, which would break if the string starts with non-word data. Seems like a good test case to include.
Test haskell/word-count that symbols separate words

Another useful test case for wordCount: make sure that non-alphanumeric characters are treated as separators between words, so that `"foo%%%bar" /= fromList [("foobar", 1)]`.
Fix paragraph tag inside of <h2>
adds a couple missing anagram tests

- anagrams must not be the source word case-insensitively
- anagrams must use all letters exactly once

Without these tests, it was possible for match functions to pass all
tests while still not being entirely correct.
haskell octal
 haskell trinary
haskell wordy
Fix flash on exercise completion. Fixes #658.
Do not transfer likes to the next submission
Introduce `liked` fields on Submission

As a first step, duplicate the existing `approvable` fields, and write
to both places. This will allow us to migrate existing data, then switch
over to use the new fields while deleting the old ones.
Use liked rather than approvable
State who liked the assignment. See #657.
Show liked checkmark on dashboard. See #657.
Don't ask for more opinions on completed exercises
Make `looks great` its own thing.

Don't tie it together with nitpicks. Move it out of the nitpick form,
and put it closer to the code so it's less likely that one would click
it by accident.
Delete unused code
Don't notify on complete (seed data)
Add notification for likes. See #657
Move the looks great button
Go etl example.