SLING-2985 : improvements in the content-browser : double click on a jcr node opens the corresponding .content.xml in the editor - editing and saving the .content.xml updates the tree in the project explorer automatically

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1520309 13f79535-47bb-0310-9956-ffa450edef68