Attrs: Simplify an option hook

Since getter was removed in fdd78fad19ea3390cd96971cd29430e36378d137
there is no longer a need to wrap option element in order to get its value

Fixes #14756
Selector: update Sizzle
Build: Upgrade QUnit to 1.14.0
Docs: Change raises to throws in README test assertions
Support: Document box-sizing was unprefixed in Firefox 29