handles "options" arg on Collection aggregate

[challet]

As seen on http://php.net/manual/fr/mongocollection.aggregate.php there is a second argument available for MongoCollection::aggregate.
It accepts for instance a maxTimeMS argument which can be very useful to increase for the aggregation process.

[Jurigag]

Phalcon/Mvc/Colllection requires changes anyway which are gonna be done in 3.1.0 or later to support both php versions.

[sergeyklay]

@challet Could you pleas rebase onto 3.1.x, amend CHANGELOG.md and add tests

[challet]

Hi @sergeyklay, I'm trying to find a documentation about using the tests suite on a custom Phalcon build. Would you have some link to help me with this matter please ?

[sergeyklay]

@challet Hello

Readme: https://github.com/phalcon/cphalcon/tree/master/tests
Collection Test: https://github.com/phalcon/cphalcon/blob/master/tests/unit/Mvc/CollectionTest.php
Example environment: https://github.com/phalcon/cphalcon/blob/master/.travis.yml

[sergeyklay]

Introduced in the 3.4.x branch. Feel free to open a new issue if the problem appears again. Thank you for contributing.