Adding minified build

Added another task to the Grunt requirejs task to build a minified version
of Xooie.  Also removed the addon files from the build process as they
have yet to be updated for the 1.0 release.
IE8 Bug Fix

Fixes #75.  Added polyfils to helpers.js to add support for
Array.prototype.indexOf and Function.prototype.bind, both of which
are not supported in IE8.