`converter.Converter.domain` doesn't match domains with trailing dot
This is important (especially) for matching .
(root).
Example:
>>> from converter import Converter
>>> print(Converter.domain.match("."))
None
>>> print(Converter.domain.match("nic.cz."))
None
>>> print(Converter.domain.match("nic.cz"))
<_sre.SRE_Match object; span=(0, 6), match='nic.cz'>