Add AJAX endpoints for bulk reindexing operations.

New endpoints to trigger reindex and to get the status of a current reindex
operation from the WordPress.com servers.
Inital stub for reindex request UI.
Adding Related Posts Module

Initial commit of a new module to make it possible to uses the
WordPress.com Elasticsearch infrastructure to find related posts.
Add RTL Stylesheets

Automatically generated on Jan 14 2014 19:04:19
Flesh out more info card for related posts

Add a screenshot and links to support page on jetpack.me for the related
posts feature.
Move Bulk Reindexing Code into Jetpack_Sync

Move trigger and status getter methods into the Jetpack_Sync class and keep
JSON endpoints in the Jetpack class.
Use Jetpack_Sync method to trigger a bulk sync on activate.
Move Reindex Triggers

Move manual reindex triggers into info card of the related posts module
from the Jetpack debugging center.
Revert Debugger Change
Merge branch 'master' into module-related-posts

Conflicts:
	modules/module-info.php
Add Module Icon for Related Posts

Props @jasmussen
Tweak Module Description for Related Posts
Simplify Configs for Related Posts Module

Remove the feature toggle for related posts by default as it must be
activated from the Jetpack dashboard anyways.
Better Wordsmithing
Use Jetpack_Options to track bulk reindex status
Use Jetpack_Options whenever possible
Fix percentage calculation
Cleanup Thumbnail Extraction

Use common code in `Jetpack_PostImages` to extract an image to use as the
thumbnail and the newly added method `Jetpack_PostImages::square_image_url()` to
squarify the image returned.
Selectively Hide Thumbnail Images

If thumbnails for related posts is turned and there are no thumbnails for
the related posts found the author's avatar will display for each result.
Prevent these cases from happening and supress thumbnails if none can be
found.
Merge branch 'master' into module-related-posts