IE: Object does not support property or method "find"

[serbel]

IE 11.0.96.00.18837 (Win7) and IE 11.674.15063.0 (Win10) throws an error:
"Object does not support property or method "find". It’s necessary to add a polyfill for IE browsers, e.g:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find

[jdreetz]

@serbel - I've added the required Polyfill in this PR - #16