* fix query builder delete

* tweak a bit

* tweak the test

* add sub document aggregation array functionality

example:
    Model::sum('subarray.*.price');

this method is much simpler as to use as complex raw aggregations

for this function a $unwind directive will be pushed in pipeline before $group

* change testSubdocumentArrayAggregate

change test for different scenarios

* rebase to latest master and fix style ci issues