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.

Will allow performance update when not using audio.
Done for benchmark purposes.

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.

Initial tentative audio support 

Closes #12

See merge request !19

Makes use of the new emukit audio code.

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.