Repaired hitting 'delete' key to delete a button.

The card view wasn't forwarding keypresses anymore.
Track ForgeDebugger HEAD
Remove leftover, broken search path.
Fix some errors in modifier flag passing.

Still get screwed up parameters in the script, though.
Don't screw up stack with 'create' instruction.
Add 'debug checkpoint' instruction.

Remove old hard-coded checkpoints.
Track Leonie HEAD for more robust debugger.
Fix changing of 'style' property on parts.

We now recreate the presenter when the style changes.