Adds youtube liquid tag support

- Works as the existing [octopress / jekyll plugin](https://gist.github.com/jamieowen/2063748)
Merge pull request #98 from nt3rp/add-youtube-liquid-tag

Add support for YouTube to Liquid Tags plugin
update readme with requirements

better_figures_and_images doesn't make it clear in the readme what
requirements are required.
Merge pull request #99 from fly/better_requirements

update better_figures_and_images readme with requirements
added the ability to override\force related_posts from the post's meta data
Merge pull request #102 from Shaked/master

Override related_posts from post metadata
Update sitemap plugin to place nicely with modified metadata

modified is a string in pelican <= 3.3 and datetime > 3.3

Sitemap used to treat it as string.
Merge pull request #103 from talha131/fix-sitemap

Update sitemap plugin to play nicely with modified metadata
Refactor and fix minor typo in sitemap code
Merge pull request #104 from talha131/cleanup-sitemap

Refactor and fix minor typo in sitemap code
Minify JSON to improve search speed
Merge pull request #105 from talha131/minify-json

Minify JSON to improve search speed
Use THEME_STATIC_DIR instead of hardcoded 'theme'

The output folder for the theme can be changed via `THEME_STATIC_DIR` setting. But the assets plugin uses the harcoded `theme` string. This small patch makes the asset plugin use the setting.
Merge pull request #107 from graffic/patch-1

Use THEME_STATIC_DIR instead of hardcoded 'theme'
The `asset_url` needs to use also `theme_static_dir`

Sorry for this mistake, I was using harcoded paths in my template.

If the destination changes in the output folder (`THEME_STATIC_DIR`) also the URL used for the assets should change.
Update readme.rst

The name of the package in pip is `beautifulsoup4`, not `bs4`.
Merge pull request #108 from graffic/patch-2

The `asset_url` was also hardcoded instead of using `theme_static_dir`
DOC: nbconvert no longer necessary
Fix error message for IPython 2.0
Merge pull request #110 from jseabold/ipython-fixes

IPython cleanup