Documentation license Creative Commons by Attribution (GEOS-5543)

Result of http://geoserver.org/display/GEOS/GSIP+89+Creative+Commons+with+Attribution

Link to Jira here: http://jira.codehaus.org/browse/GEOS-5543

Change:
- updates geoserver template with a link to creative commons license
- udpates the conf.py files to say "2013 OpenPlans"