* Move producer configuration into configure(...) method of Python API
* Enable output from OpenPose in Python API by making VectorDatum an opaque STL type
* Return empty arrays as None in Python API
* Add type_caster for Array<long long> for datum.poseIds in Python API
* Add ThreadManagerMode enum to Python interface
* Update Python tutorial in line with updated interface and add demo of AsynchronousOut mode
* Remove static_cast of ThreadManagerMode which is no longer needed
* Only set up producer in Python API when SynchronousIn is set
* Fix up memory handling in emplaceAndPop
* Pass AsynchronousOut in async out example
