Creating an Image in python from a numpy array doesn't work

[icaven]

The function create_from_ndarray() in src/python/k4a/src/k4a/_bindings/image.py has a number of errors:

• the naming of the modules used (_nd instead of _np, and ctypes instead of _ctypes)

• when the defaults for the size of the image are used (all set to 0), the correct values are not fetched from the array.

• None is not permitted as the callback in k4a_image_create_from_buffer(), it leads to the following error:

  ctypes.ArgumentError: argument 7: <class 'TypeError'>: expected CFunctionType instance instead of NoneType

• the reference count on the numpy array passed in should have its reference count incremented so that the array will not be
  deallocated when the caller deletes it

Related to the callback, in src/python/k4a/src/k4a/_bindings/k4a.py:

• the declaration of the k4a_image_create_from_buffer has the incorrect callback function type (_memory_allocate_cb instead of the correct _memory_destroy_cb).