Our interrupts are already scheduled via `mp_schedule()`. By switching
to the synchronous interface we avoid yet another `mp_schedule()` call
in the bluetooth module. This also allows the bluetooth module to not
have to use its internal ring buffer.

PNG support

See merge request !457

BLE fixes

See merge request !454

This fixes a potential system panic if there is already an interrupt pending

fix(display): Do not free user memory in blit

See merge request !453

change(mp): Plug in MP v1.14

See merge request !452

feat(mp-ble): add support for ATT client operation

See merge request !451

BLE advertisement support for MicroPython

See merge request !449

Initial MicroPython BLE support (GATTS)

See merge request !446