Fix failing sizzle tests

Here's another way to get to zero.

The changes here (from most significant to least) are as follows:

1) `HTMLOptionElement`.`selected` behavior changes. Basically, if no options are selected, and the current element is index 0 then return true.

2) a fix for the `Isolated position` sizzle test which simply fixes the context in which the selector is run. Seems reasonable to me.

3) Upgrade sizzle to latest. Fixes `Parent Element (non-space descendant combinator)`