Meta data layout

Apologies for the large commit history and change set, this is actually a merge of @indeox and I's work, that *had* to go out together for various reasons.

### What this does:
- Clean up Article, Gallery and Video templates
- Move dateline below headline
- Move dateline to left hand column at wider breakpoints
- Remove comment tab functionality (and thus a lot of JS complexity)
- Move comment count CTA to left hand column at wider breakpoints.
- Fix disscussion integration tests

### Screenshots
![Mobile](http://cl.ly/image/2B240g1d3O2e/Image%202013.09.20%2010%3A10%3A28.png)
![Tablet](http://cl.ly/image/2s1L242c3o0s/Image%202013.09.20%2010%3A10%3A53.png)
![Desktop](http://cl.ly/image/0v1S2K2p0X13/Image%202013.09.20%2010%3A11%3A19.png)