Also added support for image saving.

Test for test_blargg_instr_timing.

Game Boy color was still being mentioned, even though it was already implemented.

Fix CGB-ACID2 test

Closes #30

See merge request !27

This allows background to take precedence over objects.
This completes the CGB ACID 2 test compliance.

There may be a performance impact involved.

Previously only new ROM loading operations would take into consideration the auto-mode.
This fix affects the SDL frontend only.

Fixes issue with node 20.