pass owner of object to object's constructor
add getters
log query if logger specified
unset document's field
check if assigning subdocument to scalar value occured
allow find distinct  values
implement event engine based on symfony's component
before and after conscruct event listeners may be defined only inside document
implement deleting document by calling document's method
add tests for document's events
change dependency definition
move unused property
fix setting objects
add method to attach afterConstruct event
implement transcoding query builder to array
add expression method
add expression method
add whereElemNotMatch method
$limit (aggregation)

ITV-758
Merge pull request #3 from vetalt/patch-1

$limit (aggregation)