update pom.xml files to state Artistic License 2.0

Much like bug report #2920677, I like to see the clarification about CML using AL 2.0 be reflected in the pom.xml's around the SVN repository, such as in:

http://cml.svn.sourceforge.net/viewvc/cml/cmlxom/trunk/pom.xml?revision=1366&view=markup

where at line 142 the URL should be changed to the license version specific URL:

http://www.opensource.org/licenses/artistic-license-2.0.php

An new versioned release would be brilliant so that I could properly update CDK and Bioclipse, and allowing me to clarify to our user base, what the rights are, and to indicate we are not violating licenses, as we would if the AL1.0 was used.