This issue was prevent CH4 from working properly.
Also added TODO operations to the master volume.

The implemenation seems correct but is yet to be tested.
The coding of LFSR still needs auditing.

Also fixed small channel 3 issue

The selection mode was being returned with an inverted value.

Also avoid problem with processing extra 15th byte of the title for situations where the CGB flag is present.

Improves performance of APU by an order of maginute at the cost of less accurate emulation.

There's still no control over the channels themselves, but the basic interleaved buffer support is now coded.
There's also new support for buffer size definition in seconds.

Support for set of video, audio and timer.
Now with support for toggling audio in the SDL version.

This is specially useful for disabling APU if not used.

Using a dequeue it's possible to control the size of the queue and outdate old elements.

Now the BIOS beep works perfectly.

There's some testing pending but audion is getting perfected.

The emulator is now sounding more like a real audio player .

There are a series of hacks involved in making a constant stream of audio data to work OK with web audio.

These are temporary fixes.

Silences clippy.

Made use of queue support for SDL avoiding the callback approach which greatly simplifies the code and increases the APU accuracy.

It's stil glitchy and noisy, need to check the problems.

Still requires work to be able to be able to emulate APU together with the CPU instead of inverting the control.

There's still a lot of work needed.

This a very work in progress situation that requires stability.
The most important part is the fact that it's possible for an external entity (SDL) to call an audio tick and get a volume.