Screenlogicpy

**Changed:**

- Added debugging data:
- Included **all** unknown and previously skipped response bytes in **data**. Hopefully this will be helpful in comparing unknown values between installations with known features.
- Labeled all unknown values/data with byte offset. ex. `unknown_at_offset_24`.
- Code cleanup:
- Consolidated request lifetime management code.
- Refactored how response data is integrated into the main data dict.
- Miscellaneous code optimization taking advantage of new patterns

**Added:**

- Debug gateway function `get_debug()`. Returns a dict of the last responses to each request in raw bytes.

**Fixed:**
- Fixed leak of Future objects in protocol.

**Changed:**
- Updated friendly names for SCG Levels:
- `SCG Level 1` -> `Pool SCG Level`
- `SCG Level 2` -> `Spa SCG Level`

**Added:**
- API function `async_get_mac_address(gateway_ip, gateway_port)` to connect and get only MAC address from a protocol adapter. Supports validation of IP address and port.

**Added:**
- Additional error handling when attempting to create a connection to the ScreenLogic protocol adapter

**Fixed:**
- General async I/O reliability improvements
- Simplify message tracking
- Handle multiple SL messages in one transmission
- Attempt to wait for all outstanding requests before closing the connection on `async_disconnect`
- Correct padding on encoded strings

**Added:**
- More logging
- Asyncio gateway example
- Some general cleanup

**Removed:**
- Scratchpad folder
- Outdated examples
- Artificial 'network' delay in `fake_gateway` used for tests

This release moves `screenlogicpy` over to using asyncio. See README.md for updated usage instructions.

**Added:**

- Ability to set SCG output values for both pool and spa separately.

**Breaking Changes:**

- Most `ScreenLogicGateway` methods renamed. See README.md for updated usage instructions.
- `await` syntax now required on most `ScreenLogicGateway` methods.
- Non-async `discover()` function depreciated. Please use `async_discover()`.