Refactor image click handling. Update Sinclair placeholder image
Add notes on source code.
Fix the masks.
Update hack to release key after being processed.
Display minus signs properly for Sinclair.
Update source commentary
Fix CPU bugs, mostly conditions.

Fix AKCN to only look at N line.
Skip instruction after AKCN - makes code work, but seems dodgy.
Fix condition code handling - most ops only set, don't reset.
Update tests.
Update source code