- Introducers can now be created by specifying a file. The certificate
gets imported and declared as an introducer for the passed domains.
- Add some checks, so that the imported certificate can actually be used
as an introducer (certificate is alive, not revoked, has certification
capabilities)
- Create a command to add an introducer (with domains).
- Add a module for escaping regular expressions used in certifications
- Add some helper functions.