Adds GET endpoint /api, takes URL & DOI

* New /api endpoint
	* Takes GET requests
	* Cache enabled (client, not server-side)
	* Takes both URL and DOI
* Moved files to /lib/
	* unshorten.js now follows all redirects
	* distingush.js determines whether search
	  term is DOI, or URL as default
	* Most request logic moved to request.js
* All responses now have request errors
        * Previously if a request error, body
          was sent with URL as title
        * Now body is still sent, but with 520
          error.
* 'mediawiki' format in /lib/zotero.js changed
        * ISBN now list of isbns
	* ISSN now list of issns
* README.md created

Change-Id: Ia4b58d4b9eda3871c239c50bbacdce814bb3c134