Versions of MongoDB before 3.0 create a database when dropping the collection of a database that doesn't exist (as is done by the setUp() method).

Options can be passed directly to FindAndModify after any necessary translation/conversion.

We only use the writeConcern option if isset() return true, so we needn't complain about users passing a null value.

Helper functions are necessary until PHPC-417 is implemented and Manager getters return actual value objects.

fix doc url