Added a "composer.json" file, registered on Packagist, and configured the GitHub service hook to push new tags (and pushes) to Packagist. This allows ZeroClipboard to easily be imported as a library dependency into PHP projects via Composer.
https://packagist.org/packages/zeroclipboard/zeroclipboard
Implementation based on advice from PR #256.
If this makes you happy, you owe a special "thank you" to @drcreazy and @maxromanovsky for making the request and giving us advice!