Add unit test of pywbemcli script
Add unit test of pywbemcli script

Adds a unit test that calls pywbem cli with cmd line options and tests
the results against expected results.

This code is directly from pywbem similar function for wbemcli.  The
primary difference is the commands issues.

pywbem/pywbemtools,pywbem/pywbemtools