Fix for bug in the logic to match treenodes and graphs after load.
Fix for bug in the logic to match treenodes and graphs after load.

Changed the JSON serialisation format to better conform to the intent of
the code: Graphs are no longer serialised as a global list, but
recursively. This also has a positively effect on load performance, since
it gets rid of a linear search when resolving graph references.

engijs/engi,beni55/engi,vizorvr/patches,beni55/engi,vizorvr/vizor,engijs/engi,vizorvr/patches,beni55/engi,vizorvr/vizor-create,vizorvr/patches,vizorvr/patches,vizorvr/vizor,engijs/engi,vizorvr/vizor-create,vizorvr/vizor-create,vizorvr/vizor,vizorvr/patches