Fixes #507 - character limited refactor

- Fixes #507 - makes it so the character limited can be attached to any
element with the ‘character-limited’ class attached.
- Allows overriding of defaults on the character-limiter.
- Makes show/hide element a single element that’s not constantly
re-created.
- Moves character-limiter CSS out of #detail-info.
Merge pull request #604 from codeforamerica/507-character-limiter

507 character limiter