started process of adding hooks. I've added several now and move a lot of logic so they're called by these hooks

Added javascript which shows/unshows related content, cleaned up code and improved documentation, css improvements for Garland (default theme)

Added UI for adding memetrackers and picking content_sources and refreshing memes. Plus a number of minor bug fixes including #285094

major optimization effort - store distance scores now in table - dropps meme calc time by ~75%, fixed click recording for anonymous users

added unique keys to memetracker_content and memetracker_click database to ensure content and clicks aren't recorded twice

Initial commit of memetracker and machinelearningapi modules. Happy day! Memetracker finds and displays to a community in real time the most interesting conversations and memes as they emerge.