Add SSDPResponse::sendto method and tests (#96)

Add SSDP CLI with discovery command (#94)

* Refactor package structure into more modules
* Deprecate old import paths
* Add Pygments lexer plugin
* Improve documentation
* Add CLI including a discovery command
* Add IPv6 support

Fix missing pytest call in CI suite

Bump isort from 5.9.1 to 5.9.2

Bumps [isort](https://github.com/pycqa/isort) from 5.9.1 to 5.9.2.
- [Release notes](https://github.com/pycqa/isort/releases)
- [Changelog](https://github.com/PyCQA/isort/blob/main/CHANGELOG.md)
- [Commits](PyCQA/isort@5.9.1...5.9.2)

---
updated-dependencies:
- dependency-name: isort
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Transfrom module into package

Switch travis-ci python version from 3.7-dev to nightly