Misc fixes backported from upstream svn
    
    - Fixes Upstream Bug #723568
    - Fixes Bug #1071689
    - Fixes a bug that left development enabled (#1066710, #1068719)
    - Fix an issue in get_toplevel_name_for_uri()
    - Make sure filetreemodel_build_dir() can handle a NULL (invalid) toplevel
    - Fix a couple of miscellaneous bugs