Add named scopes and methods for "status"

Fix #50
Merge branch 'status-as-model-property' of github.com:sarahsemark/suitor into status-as-model-property
Fix a little bug that caused posting page to spew errors.
Set up basic buttons for filtering.
Arrange filter buttons in a drop-down menu.
Add checked/unchecked toggle effects.
Show archived posts as seperate control button.
Hide dropdown menu of filters if clicking elsewhere.
Filtering should show the right postings
Merge master into filter-postings
Merge branch 'filter-postings'