self if it isn't there... This lets us update all children before
sending them down the pipe...
set the size properly...
make FSDirectory have proper order for inheritance, so the Item
checkUpdate doesn't get called instead of the FSObject's
[git-p4: depot-paths = "//depot/": change = 767]
make Containers contain their own list of children...
add the containing ContentDirectory to the Items so that they can
add children to themselves...
[git-p4: depot-paths = "//depot/": change = 762]