Permissions patch to fix BZ_951305

This patch adds permission and file ownership setting features to the shim. "chown" and other permissions related functionality to the shim.    It also adds a correct implementation of setOwner, so that group and owner setting is honored.  Corresponding unit tests are included which create files, and change their ownership.

This is the "second half" of the permissions patch in BZ908898, which fixed permissions reading.