New developer-only SDK 1.4.0a2:

- Using Deunan Knute's ARM7 so DISDL/DIPAN are written properly
- Reenabled use of DISDL/DIPAN
- Tried to fix 16-bit samples. Failed smirk

Reminder: do not download this if you want to just listen to music - this is for folks who want to contribute to the AICA emulation only right now.