Run through all formatters when selecting text and set active states (if required). Also set once a button has been pressed.
Merge branch 'master' into feature/show-selected-format-btn

* master:
  Drop the tweet URL from the ST options in favour of overriding the method on the block using the setBlockOptions method. As mentioned in #38.

Conflicts:
	sir-trevor.min.js
Merge pull request #47 from madebymany/feature/show-selected-format-btn

Set active state on format buttons