Minor bugs fixes and a few new features.
**Added**: Correctly implemented `signal SIGTERM` command handling in send_command and added `send_sigterm()` function to issue the command. Many thanks to [D0han](https://github.com/D0han) for the PR implementing some of this.
**Changed**: `NotConnectedError` now raised if `send_command()` (or anything which uses `send_command()`) called before calling `connect()`.
**Fixed**: `get_status()` will now explicitly ask for the status in format 1.