We want to have such functionality be aggregated in a class.

For wordlists we require a certain filename format. This is
described by a regular expression we introduce hereby.

This function provides pure WordList functionality and should be
part of this class therefore.

We do not need `basestring` (or some Py3 equivalent) to check for
strings.

The functionality is replaced by the WordList class.

We also support cryptographically signed wordlists with WordList instances.

Make sure signed entries are stripped also if dash-escaped.

Create a single place where lines of wordlists can be refined,
regardless of their mode (crypt-signed or not).

Many wordlists have format "NNNNNN<tab>some-term". We try to
detect lines of this format and will parse them to get the term
(removing numbers and whitespaces).

and do not strip() if done already.

We need this regular expression to strip entries in wordlists like
the original 7776-terms wordlist from diceware.com.

As described in RFC 4880, dashes in wordlists might be escaped.
We have to take care of this when extracting wordlists.

We expect more wordlist-specific changes, regarding signatures etc.

This one is best suited for real dice passphrases.

There is no need for us to enforce lowercase wordlist names. It
could even confuse people.

We will certainly provide other english lists as well. Therefore
we need something for distinction.

Also this method now handles names instead of language codes.

We will drop the assumption that wordlists are generally organized
by language. There are, for instance, many different language
lists available in english for many different purposes.

Therefore we will support different names for different wordlists,
but the names do not neccessary depend on a language (only).