- Support JSON-formatted output

- Add a validation warning cache to speed up repeated runs

- Cache validators for a slight speed up in validation times

- Drop property type guessing. Mostly this covered 4 byte properties to
  be uint32. Now those will cause warnings.

- Handle type collisions for "gpios" and "cooling-levels"

- Some fixes to decoding matrix properties correctly

Schemas:
- Add mbox-controller and power-controller schemas

- Restrict reserved-memory entries to 1 "reg" entry