Adding new plugin Code Include

This plugin allows you to include other files as a code block with
syntax highlighting in ReST articles. You'll need docutils>0.10, as
there was a circular import bug in the 0.10 release.
Some minor tweaks: documentation, py3 compliance

Pulled most documentation out of code to avoid desync
Fixed unicode literals
Fixed except syntax for py3 compliance
PEP 8 fixes
Whitespace fixes
Add a multi_part plugin

It list all parts of a blog post, helping to create a navigation menu between all the parts
Import the sitemap plugin from getpelican/pelican@024ecb30
Merge pull request #13 from abackstrom/import-sitemap

Import the sitemap plugin from getpelican/pelican@024ecb30
Adds GoodReads activity plugin
Adding LICENSE file for Affero GPL
Merge pull request #15 from abackstrom/affero-gpl

Adding LICENSE file for Affero GPL
Initial Gallery Plugin Commit
import plugins from core and restructure repo
move tests to plugin folder
teach plugins with dependencies to behave
Merge pull request #18 from avaris/import-plugins

Import plugins and restructure repository
Adds Extract table of contents plugin
add w3c validator plugin
Merge pull request #19 from zemanel/w3c-validator-plugin

add w3c validator plugin
Minor improvements to W3C Validator plugin README
Added initial stab at figures and image widths plugin.

Signed-off-by: Duncan Lock <duncan.lock@gmail.com>