After 11 months, a new version of maxYMiser DMA.

Improvements this time:

* New STe native DMA mode. Almost zero CPU overhead on STe, full 50kHz quality
* New preset pattern feature, including 'empty' and 'note off' patterns
* More graceful handling of disabled timers
* Much improved support for Atari TT (thanks to SH3 for the loan of his TT)
* Memory saving minimum DMA volume control
* Updated SNDH_CPU.TTP
* Other small bug fixes