Link and attribution correction

[BriceShatzer]

Fix for issue #34

• When John Resig forked this repo, he added a link in the Readme to acknowledge the original project. Unfortunately, it appears that a PR he authored was accepted and this new attribution overwrote the previous acknowledgment of
  Shortcut.js. This returns that acknowledgment.
• Fixes the invalid link found in the masthead of the script file in addition to returning the previously removed acknowledgement of Shortcut.js