0.9.0-alpha 2025-02-17 GODOLPHIN HILL

• New system for node parameters - the TaggedAggregate system. All nodes
  updated to this where it makes sense.
• Batch runner (pcotbatch) first draft, which allows a graph to be run
  from the command line with inputs and nodes able to be modified with a
  text file, and outputs able to be captured and saved.
• Complete rewrite of manual register node
• "PARC" input and output file format - allows multispectral images with
  uncertainty to be stored (and other data types too)
• Various bits of refactoring
• Issue fixes
• Yet more tests
• Nodes are now created by left-click dragging from the palette
• Nodes which have been renamed from their defaults have their name text
  shown in bold
• Forced to downgrade minimum Python version to 3.9 temporarily