DOXIASITETOOLS-90: site inheritance controllable
* Added combine.self attribute to site descriptor, by analogy to plugin configuration.
* exempted some batik from the enforcer; otherwise won't build.


git-svn-id: https://svn.apache.org/repos/asf/maven/doxia/doxia-sitetools/trunk@1604218 13f79535-47bb-0310-9956-ffa450edef68