Added SoundCloud tag
First commit.
testing
Added logic to load mathjax only when tag mathjax is present in post and index templates.
Changing names and correcting default values.
Fix Flake 8 issues
Add missing closing tags in base templates
Fixed mathjax config description in conf.py.
Added an aditional back slash to ipynb config example.
Twitter Card support.
Wordpress import: do not write 'None' as a description if it isn't present.
Support Open Graph aswell.
Updated documentation.
open changelog for master
Merging https://github.com/ralsina/nikola master
Merge pull request #315 from localvoid/fix-base-templates

Add missing closing tags in base templates
updated changelog
Merge branch 'master' of https://github.com/ralsina/nikola into twitter_cards
Merge branch 'master' of github.com:ralsina/nikola
Small improvements based on Robertos review.