Gallery lightbox


![image](https://cloud.githubusercontent.com/assets/960919/4253675/44c1c278-3aa3-11e4-897c-001e790bd98e.png)


finally
![image](http://media.giphy.com/media/UdqUo8xvEcvgA/giphy.gif)
manually setting transitions to vendor prefixes which isn't really possible with a mixin? some versions of browsers need the prefixed version and some not. not sure if I'm even covering all cases here. hard to know. shotgun approach...