Lots of methods are untested

There are many methods that do not have any sort of test for functionality.

They include:
- `set_digital_port_bit_direction`
- `read_digital_port`
- `read_digital_port_bit`
- `write_digital_port`
- `write_digital_port_bit`
- `read_channel_temperature`
- `read_memory`
- `write_memory`
- `get_item`
- `set_item`
- `get_burnout_status`
