Minor changes

Moving out nested function, some comments, changed fetchAndUpdateFeed to
build args object instead of using object literal
Moved feed.js into feed folder

Updated deps
Split up feed.js

Preparing to modularize feed, created several files that are more
"coherent" around the general purpose of each of the functions in each
file. Updated some comments, updated some whitespace, updated file deps
Modularized feed/add.js
Added some comments