Merged Xml stuff into the "viewer" package.

--HG--
rename : viewer/src/main/scala/org/podval/judaica/xml/Xml.scala => viewer/src/main/scala/org/podval/judaica/viewer/Xml.scala
rename : viewer/src/main/scala/org/podval/judaica/xml/XmlFile.scala => viewer/src/main/scala/org/podval/judaica/viewer/XmlFile.scala