Added an Array.forEach polyfill so jasmine works on IE < 9

ie6/7/8 doesn't have `Array.forEach()` which the jasmine framework handler is using (maybe others too, but haven't tested them). Most code being tested probably already provides a polyfill for it, but some doesn't. It was causing a js error and for the test results to never be recorded and for the browserstack session to hang and timeout.
I thought about just rewriting the loops to plain old for loops, but thought a polyfill would be a more sustainable way to go.
I added a polyfill.js file so that other polyfills can be added to the same file as/when they are required.