IE 9+ fixes

* Fix making PUT/DELETE requests by uppercasing the HTTP method name
* This also fixes PATCH for Chrome/Safari
* Fix requests with undefined body on IE
* IE 9 fix for connection error
* Fix CSS being applied to test suite

The only test that now fails is the FormData test on IE 9. Maybe we should skip that test if FormData is unavailable?
> Ok, section 2.1.1 says to uppercase as normalization so this looks good.

To be fair, it only says normalization is good if it matches one of the whitelisted methods. We would also have to throw a TypeError when encountering one of 3 "forbidden" methods. I feel that we wouldn't gain much by following these details word by word, though, so I'm OK with the simplistic approach here.