Made :controller/reset replace previous history state

Problem reference: https://trello.com/c/u5A0MOln/630-back-button-doesn-t-work-when-accessed-via-lightbox

This fixes history bug when hitting browser's back button while `lightbox` is open or after closing.
Lightbox generating history issues examples can be found for ex. on [interests](http://www.lonelyplanet.com/family-travel/best-of-family-travel) or on any Thorn Tree's thread/topic page - just click on any username.

`:controller/reset` hasn't been actually resetting browser's history - the replaced state, after clicking on lightbox trigger, stayed in browser history and had never been replaced back on `reset`.

I don't know all the use cases of this event though - @Ianfeather, @i-like-robots, @remybach - can I have your opinion on this?