Tmuxp

- 530 Plugin system

- Add plugin system for user customization of tmuxp
- Add tests for the plugin system
- Update existing tests for the plugin system
- Add the plugin interface to the tmuxp package
- Add in depth documentation for the plugin system

Thank you joseph-flinn!

- 665 Support for passing tmux config file (`-f`), thanks jfindlay! Fixes
654

- 651 Fix packaging issue with click, thanks dougharris! Fixes
649

- 647 Adding option to dump `load` output to log file, thank you
joseph-flinn!

`tmuxp load file.yaml --log-file yourfile.txt`

Adjust log levels:

`tmuxp --log-level DEBUG load file.yaml --log-file yourfile.txt`

- 643 New command `tmuxp debug-info` for creating github
issues, fixes 352. Thank you joseph-flinn!

(v1-6-1)=

- 641 Improvements to `shell`

Thanks [django-extensions] (licensed MIT) for the shell detection abstraction.

- Deprecate `shell_plus`
- `tmuxp shell` now detects the best shell available by default
- Python 3.7+ with `PYTHONBREAKPOINT` set in env will drop into `pdb` by
default
- Drop into `code.interact` by default instead of `pdb` if no third
party shells found
- New options, override:

- `--pdb`: Use plain old `breakpoint()` (python 3.7+) or
`pdb.set_trace`
- `--code`: Drop into `code.interact`, accepts `--use-pythonrc`
- `--bpython`: Drop into [bpython]
- `--ipython`: Drop into [ipython]
- `--ptpython`: Drop into [ptpython], accepts `--use-vi-mode`
- `--ptipython`: Drop into [ipython], accepts
`--use-vi-mode`

[django-extensions]: https://github.com/django-extensions/django-extensions