This reverts commit 866c2306.

This is done at a rate of every 5 seconds.

There are many quirks to how this works but the unfreeze and thre length clock on enable are the most important ones.
For more information on these options check https://github.com/retrio/gb-test-roms/blob/master/dmg_sound/source/03-trigger.s.

We're currently in the 02-len ctr.s test.

Also added support for image saving.

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

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