Fixes for "#50 Result output should not contain or require any logic"

I've added the `scripts` option, which takes an array of files and inserts script tags with src attributes in the styleguide template. Local files will be copied to the styleguide output folder and included from there. File paths starting with a schema (http://, https://, //, file://) will be used as they are.

I moved all the JS logic out of the template and into a new `scripts.js` file which is the default for the `scripts` option. I also cleaned up that code a little bit.

In the template we are left with one script tag per result to hold the html, one script tag to hold the results template and its assets, and the new scripts partial.

As a side effect of these changes assets can now be loaded using the shorthand `//` for `http://` or `https://`.