Add edit icon to action toolbar

The action toolbar should include an 'edit' icon.

Clicking on the edit button enables the user to change the original values they inputted when creating the item.

![screen shot 2014-09-18 at 1 44 31 pm](https://cloud.githubusercontent.com/assets/1521387/4319236/b6042fd6-3f29-11e4-9835-b19d52ea5b4d.png)



I've mentioned something similar on an earier PR. Not all routers will have a 'default' endpoint. We're going to need to provide a way of handling the way router forms are displayed depending on the router type. The same will go for conversations and channels probably.

For earlier PRs, I've said we can leave this kind of stuff for later PRs, but I'm worried we're making it harder for us to do that refactoring each time we add something like this, so I'm inclined to say we should either start handling this kind of thing now, or directly after this PR.

@andreit thoughts?