Component: `message_board`

A Mokuji component that provides a message board based on social media feeds.

Dependencies:

Component: api_cache (depends on plugin codebird)
Component: media (depends on plugin plupload)
Plugin: readability

TODO:

Parse author information better: table with avatar, uri, name, id, etc.
Improve the readability plugin.
Cache message images.
Implement a cache cleanup for api_cache (since parameters change over time)
Implement an update delay for feeds.