Adjust socket names to match spec, adjust GLB import and export to match spec

[hybridherbst]

In the spec, a lot of sockets use "value" as name, but in this repo it seems its mostly "val":
https://github.com/KhronosGroup/glTF/blob/interactivity/extensions/2.0/Khronos/KHR_interactivity/Specification.adoc#36422-pointer-set

See also #24 (comment)

Also the nested "graph" object should be dropped – it's not used in the current spec:

[hybridherbst]

Hey @mattmacf98, I made several fixes and improvements here:
https://github.com/needle-tools/glTF-InteractivityGraph-AuthoringTool/commits/dev/

• added a partial implementation of KHR_node_visibility (needs Babylon 7 for a full implementation, which already has the extension already either ways)
• hardened the graph layouting (some cases with exceptions at the moment)
• adjusted import/export to not assume the KHR_interactivity.graph.nodes object
• fixed sequence nodes not working with arbitrary input names
• fixed flow/delay to use "done", was "completed"
• fixed pointer/get and pointer/set to use "value" instead of "val"

Let me know if you want individual PRs for them. But you can also cherry-pick things out of there if that's easier.

[mattmacf98]

Thank you so much! I just read through all of the changes and they look good to me, would you be able to open a single PR for all of these together? If not, I can just go through and cherry pick them

[hybridherbst]

Sure, I did that here now:

• Various fixes #29

As mentioned there this is partial – it would probably be good to do a pass over the naming of things but I didn't get to that yet.