Make use of the $set, $unset, $push, $pull etc..
Issue #41 adds in $set.
I would like to take some time to tackle $unset, $push, and $pull.
$unset, however, is questionable - since an Object in morph has very well defined structure, what would be the purpose of removing a property from the Object? I can't really envision a situation in which this occurs..
$push and $pull are useful for embedded documents or adding and removing embedded references.