Webmention-tools

With this release, the ownership of [webmentiontools](https://pypi.org/project/webmentiontools/) changed.
Due to [PEP 541](https://www.python.org/dev/peps/pep-0541/) the package had to be renamed.

You can find the new updates now on [webmention-tools](https://pypi.org/project/webmention-tools/).

If you have ideas, please fill an issue and have a chat :-)

New features:
- discover webmention endpoints in the Link HTTP response header
- don't verify SSL certs. python-requests's verification is overly aggressive.
- lets clients provide the webmention endpoint URL if they already know it, e.g. if it's cached from a previous send.
- discover webmention endpoints in `<a>` tags as well as `<link>`