Refactor content meta

Changes to lefthand meta - as requested by @cantlin 
(1) Display section tags in keywords() 
(2) In the meta top left the following logic is followed 
(red arrow) show first keyword apart from for Cif articles, in which case show 'comment is free' 
(blue arrow) show a series tag when there is one, if not show the first blog tag that **isnt** cif

Meta
![left-meta](https://cloud.githubusercontent.com/assets/986155/4814939/4074dc9c-5ed3-11e4-8bed-b2e30f9bf8d4.png)

Taglist
![tags](https://cloud.githubusercontent.com/assets/986155/4814946/53931668-5ed3-11e4-915c-2ca28da1d5d6.png)