Loader is not a lot more generic and deserialization code moved to generators.
There is now a small dice button on nodes that create random patterns that can be used to freeze the seed. Frozen nodes can thus be moved without affecting the seed.
Graph nodes can also transmit their seed to their children (this behavior can be enabled/disabled using the dice button at the top right of the graph pane).
Moved handling of the "global" definitions of shaders into main shader generation code.
Added group creation (does not create inputs yet, and remotes should be cleaned).
updated all preview meshes (to fix problems with depth).
