Fix WebUSB serial (#55)

Reinstate serial after flashing to fix starting of serial after flashing (main issue and related issue 1)
Don't start serial when flashing to fix flashing issues (related issue 2)

Fixes microbit-foundation/python-editor-v3#1209

Rename writeUart with uartWrite (#54)

Added connection-specific interfaces and factory functions for export…

…ing instead (#50)

* Added specific interfaces for different connection types. This is helpful for mocking.
* Exported new factory functions for creating the connections instead of the class.
* Updated demo and docs to match changes.

Use TypeDocs to document API (#52)

Export a few missing types flagged by the docs generation. Some odd cases remain but not clear that exporting is the right plan.

Add magnetometer service (#48)

Bluetooth UART support (#46)

Add error logging for bluetooth connection failure (#45)

Update serial error message name (#43)

Improve serial error logging (#42)

Fix event class export