Fixes #91 - notice states

Adds different states for the notices (was going to be views, but
that’s not necessary). Provides “unread”, “read”, “undeleted”,
“deleted” states for notices. Notices can be read and optionally
deleted from view.
Style adjustments

- Increases min-height of notice list.
- Increases and right-aligns delete button.
Merge pull request #99 from codeforamerica/91-separate-message-views

Fixes #91 - notice states

Lookin' sharp.