Fixes GCC compilation warning.

1. create_sub_devices requires use of keyword argument parition.
   Usage is d.create_sub_devices(partition=4)
2. Plugged possible memory leak in create_sub_devices_by_counts
   which memory allocated for array would not be freed if sub-devices
   vector was returned NULL
3. Changed signature of create_sub_device_by_counts from accepting object
   of type list, to accepting any object, which is checked to be Sized
   (len(obj) is expected to work), and Iterable, i.s. iteration of
   elements works
4. Changes to accept all integral types, such as np.int32, not just python int.
5. Got rid of _raise_create_sub_devices_exception function, and replaced
   it with explicit raise CreateSubDevicesError(message)