Some minor fixes and extra features plus a move away from the `rotate` property to a `set_rotate` which will fire an exception and not just fail silently if typo'd. For a detailed rationale, see: https://github.com/pimoroni/scroll-phat/commit/929c06848967e4f0849c3fe1ba33bc35db9a1bae
- Added `set_buffer` method which overwrites the complete Scroll pHAT buffer
- rotate setting now a `set_rotate` method which accepts `True` or `False`
- tidy up