BRANCH: Underscore.js & Javascript objects

Made Record, Track, and Video objects. After XML parsing, Record objects
are constructed and used to populate the HTML elements. Added
Underscore.js for array manipulation and because I want to learn how to
use it. Initial processing time is a lot longer than without js objects,
so I'm branching instead of just committing.
Added CoverObj and updated loadCover function

Added Cover object and updated code to store URI's in RecordObj, and to
pull these values when loading a cover.
Added object prototype

After watching a Pluralsight course on structuring Javascript, I wanted
to practice a bit of what I learned, so I added a Record object
prototype and encapsulated a bunch of the functionality.

I'm not sure whether this is what caused a million errors, or if they
were there before and I didn't notice them, but in any case, they are
fixed. _.reduce() is still broken, but I commented it out for now.
Changed "typeof" to "_.is[String|Object|etc.]"

Changed all of the hacky if(typeof x === y) to Underscore "is"
functions. Added code to fix multiple artists, formats, etc. Changed
object names of TrackObj, etc. (removed "Obj"). Basically, I got a lot
of stuff working that was broken.
Removed annotations from artists & labels

Discogs stores artists with the same name as "Name (1)" and "Name (2)".
Since I don't have any duplicate artists in my collection (and if I do,
I don't think it really matters), I added a regex replace to remove
"space(number)" from all Artists and Labels. I don't think this shows up
anywhere else, but if I find something I will fix it then.
Optimizations

Switched appending tracks, videos, and covers to use an HTML string to
improve performance.
More optimizations, Show/Hide by format

Optimized the HTML list creation. Added in an attribute for record size
(12, 10, 7), and added method to set size based on format description.
Added buttons to show/hide records by size.
Added "Sort by Format"

Added button w/ event to sort records into 12"/10" and 7". Changed
'.records' to '#records' for faster selection. Updated some CSS to fix
list.js error.