Allows a user to undo the last archive/delete

[davidfurlong]

Not pretty nor merge ready.

I want the last action to also be displayed in a sentence in the bottom s.t. we can give guidance to people who are a bit confused at what happened. This is why it is the bottom center and not just an undo button in the bottom right. Additionally it should go away if there is nothing to undo

fixes #320

[willzeng]

Looking good man. :+1: for the guidance messages and then should be looking gtg. Probably easiest to do with a dismissable alert: http://getbootstrap.com/components/#alerts

[davidfurlong]

Probably easiest to do with a dismissable alert: http://getbootstrap.com/components/#alerts

I'd rather put unstyled text in the bottom next to the Undo.. Example

Archived "David Furlong" and 5 connections. Undo