Support for Pushing an artifact given GAV

This PR replaces pushing using the warFile parameter with pushing given an Artifact GAV (GAVT actually).  The default value of the artifact GAV is the current project's GAV.  So it should be able to replace the default behavior provided by the warFile property, which appeared to have been deprecated before.

It also supports pushing the GAV given the -Dcf.artifact system property.

Have a look.  If you want me to put warFile back in I can do that though I think using the GAV default works better for more types of projects (jar, ear, etc.)

Added a few tests though this functionality is difficult to test so hopefully it is good enough.

Executing mvn cf:push from a "war" project still pushed a newly, not repository downloaded, artifact in my tests.

Also fixed a minor typo in my skip PR.

Mike