Record data now represented the same way everywhere, thus easily interchangeable. Also took out youtube functionalities into its own script file.
Prettified playlist.js.
Merge branch 'record-data-structure'

It was needed to use a universal representation for record data.
Before, it was represented in different structures in the search results (not yet printed), in the DOM elements, and in the server database.
Now, we can easily transfer between these.
I also changed the structure of playlist.js, now we can have a better overview on its methods.