aheckmann/mquery — pull request #31 by ashtuchkin (2014-01-30 06:40:38+00:00)
Title: Added correct cloning of ReadPreferences.

Fixes #30.
Problem was with cloning `options.readPreference` in `Query#_optionsForExec()`.
It was cloned to a simple object, which didn't work well with Mongo driver.
Not it is cloned to another ReadPreference object.

Test added.

Also removed unnecessary `{1}` from ObjectId checking regexp.