Buffer node instance events during load

[Fydar]

The sequence in which a graph is instantiated into the game should be as follows:

• Create the GraphInstance from the Graph.
  • Instantiate all the node instances.
  • Assign connection outputs from save file.
  • Map inputs and outputs of all nodes.
• Call GraphInstance.Setup().
  • Prevent events from firing.
  • Run the node instance .Setup() method.
  • Allow events from the .Setup() method to fire.

This means that, whenever a node is loaded from a save file or instantiated for the first time, the node will act using it's default values, and then change the values to it's desired ones.

Events need to be buffered during this loading phase as the nodes that haven't been .Setup() yet cannot act on the event.

Event buffering will also be useful to prevent nodes firing more events than nessessary.