Add support for Havana missing features in Windows driver

The following features were added:

-copy_volume_to_image (Havana)
-copy_image_to_volume (Havana)
-get_volume_stats (Havana)
-extend_volume (Icehouse)

The test mocking based on binary pickled files were replaced by mox.

Change-Id: I92c681280d6f7b85bcba7a5e3513f2bdb6c13f1d
Implements: blueprint windows-storage-driver-extended
Merge "Add support for Havana missing features in Windows driver"