Add xhtml namespace to avoid xmlns="" in output.
Add xhtml namespace to avoid xmlns="" in output.

rackerlabs/rackspace-docs-maven-plugin,stackforge/clouddocs-maven-plugin,stackforge/clouddocs-maven-plugin,rackerlabs/rackspace-docs-maven-plugin,inocybe/sdndocs-maven-plugin,stackforge/clouddocs-maven-plugin,rackerlabs/rackspace-docs-maven-plugin,rackerlabs/clouddocs-maven-plugin,stackforge/clouddocs-maven-plugin,OCselected/clouddocs-maven-plugin,inocybe/sdndocs-maven-plugin,OCselected/clouddocs-maven-plugin,inocybe/sdndocs-maven-plugin,rackerlabs/rackspace-docs-maven-plugin,rackerlabs/clouddocs-maven-plugin,rackerlabs/clouddocs-maven-plugin,OCselected/clouddocs-maven-plugin,OCselected/clouddocs-maven-plugin