to separate scene display from editing functionality. Load and
initialize managers in a fashion that more appropriately hides the
implementation details. Tidied comments up a bit.
git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@103 542714f4-19e9-0310-aa3c-eee0fc999fb1
code-sharing between the tileset and scene XML antics.
git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@87 542714f4-19e9-0310-aa3c-eee0fc999fb1