Document, rename, and make tests for eeState

[OscarGodson]

Right now eeState is on the prototype and it keeps track of state in an object like:

{
  edit: true
, fullscreen: false
, loaded: true
, preview: false
, unloaded: false
}

This could actually be extremely useful for a developer. It works fine as AFAIK.

The public facing API could be something simple like:

editor.getState(); // returns everything
editor.getState('fullscreen'); // returns true/false if it's in fullscreen or not

[OscarGodson]

I'm thinking about changing getState to just is. You could then use it like:

if (editor.is('fullscreen')) {
  // Do stuff.
}

Doing this in 0.1.2 because I'd like to use it internally for ticket #146 and #152 where I'll be working with editor states more.