* Do not use platform DMA12 controller, which has no dedicated IRQ line
  (Raspberry Pi 1-3 and Zero).
* FIXED: M/S mode in class CPWMOutput did not work on channel 2.
* FIXED: memmove() did not work together with circle-stdlib project.
  Now always implemented in Circle itself.
* doc/qemu.txt updated to refer to patched QEMU v6.0.0 to be used
  with Circle.
* FIXED: doc/stdlib-support.txt referred to removed build.bash script.