Various improvements

- The order of registers printed in loopvars is now deterministic.
  This enables diffing the output with a previous version.
- Generating separate graphs for single banks.
- Added some game specific idioms - these will need to be refactored.
- Refactored operands and operators a bit
Add export GUI

Implement the window in Tkinter, create an exporter task running
in a separate thread. Refactor code to enable creating database
connection from a non-main thread.