Decide on and document browser support

[baer]

I came across this block in the test code which refers to some IE8 polyfil and I didn't really understand why it had to be there. Is this for the test runner? Probably worth documenting that tests won't run in old browsers if that's the case. On the frontend the only opinionated piece of frontend code is the inclusion of lodash which should go down to IE6 so I don't see any reason (other than the tests) the project wouldn't support down that far on that.

[divmain]

This was the only place that was IE8 specific, and it was wholly unnecessary.