Allow additional query parameters on URL.
Return protocol version from `xcop.html`.
Remove sample origins and default `checkWhiteList` to false.
Add a `destroy` function on the returned `xhr` (both proxied and non-proxied)
Updated `readme.md`.
Easier to use white list.
Pass `version` when retrieving `xcop.html`

So server can heavily cache if it so desires (max-age = one year).
Bump the version to 0.0.5