delay-mode-hooks on markdown-mode. Fix #159
delay-mode-hooks on code blocks
Activate major-mode when editing code-blocks
Make entire code-block a single button

This fixes a bug we had. Hitting TAB on a codeblock would move us to the
next line on the code block, instead of going to another button. Now the
entire code block is a single button, so that is fixed.
Display comment score
Support editing comments.
Fix buffer not updating after posting answers/edits.
Close compose window when buffer is killed.
Refactor comment validity checking
Do comment validity checking on edits too
Hotfix Don't use string-trim. Fix #164
Don't fill comments. Affects #141
Refactor and simplify sx-question-mode--skip-FOO functions.

They no longer need to worry about restoring point. Just move point to
its destination and return non-nil if it worked.
Don't fill headlines
Reimplement reference not-filling
Reorganize functions.
Fix return values
Fix score checking
Merge pull request #162 from vermiculus/comment-enhancement

Comment enhancement
Merge pull request #160 from vermiculus/better-modes

Better major-modes