ColecoDS

What's New:

- Ported the AY sound chip driver from FluBBa to improve MSX1, Einstein and Coleco SGM games.
- Ported most recent SN sound chip driver from FluBBa.
- Allow more than one keyboard press at a time for the MSX1 so keyboard-mapped keys work properly (i.e. UP and SPACE at the same time)
- Cleanup across the board - save states optimized.