The document tree macro should display the tree of spaces when showSpaces=true.
Implement nested spaces support at database level
Make sure the document tree continues to work when nested spaces are enabled
Add basic support for nested spaces to the Solr Search API
Provide API and storage for optimized space related queries
Add an option to merge the space home page node with the space node in the document tree
The query used by the Document Tree to get the nested child pages is very costly
Modify the Spaces and Space Index Macros to support Nested Spaces by using a Tree instead of a List