New cli object factory for simplifying cli object creation
Added exceptions and updated review comments
Updated Host and HostGroup CLI classes.

* Added missing cli methods for both classes;
* Make use of the new SSHCommandResult return object (requires pull
  request #172);
Merge pull request #178 from omaciel/update_cli_hostgroup_class

Updated Host and HostGroup CLI classes.
Merge remote-tracking branch 'upstream/master' into cliobjectfactory
Updated factory changes
added docstring
more optimization changes
one more optimization :)
Merge pull request #177 from sthirugn/cliobjectfactory

New cli object factory for simplifying cli object creation
Improve logging
Merge pull request #181 from elyezer/master

Improve logging