32x: improve pwm accuracy
32x: implement dreq1, improve dmac
32x: move sh2 peripheral emu code to it's own file

also adds 16byte dma
32x: map dram correctly on 68k side
32x: some accuracy improvements
32x: fix some more timing problems
32x: memhandler improvements

- use consistent read tables (with write)
- use sh2 ptr instead of id
- place data_array/peri_regs in sh2 struct