Query builder should support passing options to count command

[jmikola]

I believe the line in question is here. We likely need to select relevant options from the $query array and merge those in with the local $options variable, which originates from $this->options and ultimately the Builder::getQuery() method.

In addition to the options outlined in the MongoDB manual (e.g. 'hint', 'limit', 'skip'), this leaves the user no way to pass a timeout (be it client or server-side).

For added context, support for additional count command options was implemented in #224.