The barest of HTML
Shaping the body, adding basic CSS structure
Adding and shaping our topmost container div
Adding structure and styling for top panel with album cover, track info
Basic structure and styling of the tracklist, bringing in some fonts.
Some subtle styling of an overlay shadow for the cutout metaphor.
Adding controls for sort tracklists by headings.
Building up basic JS, overall structure of how the tracklist will be populated
Adding the structural functions, CSS to generate and format rows in JavaScript
Adding structural functions for generating the cells and content themselves.
Adding code to generate and style the spotify embed
Adding the remainder of Spotify API functionality for analyse()
Adding the all the EchoNest functionality that analyse() requires.
Adding the Processing code to plot EchoNest loudness data as a background of each song's row.
Adding basic playback functionality to set the current track and show track art, info
Adding the JS controls to hook into sorting by heading. \n Also fixing a minor bug in how we were treating tracks without tempo data.
Cleaning up JavaScript organization, pulling out EN and Spotify data, making Processing local instead of remote.
Prettifying JS & HTML with HTMLPrettify
Adding README, along with relevant screenshots.
Tweak to clarify language, logic in  direction setting.