Why:
- Some boards have multiple I2C interfaces
- Control when TwoWire.begin() is called
This change addresses the need by:
- Option to not begin() Wire
- Always be in configured state (no null ptr crash)
- Internally use TwoWire pointer
- Add example of new functionality
- Add possible I2C addresses
- Update I2C address in example to be within 0 - 127 range