We have to check for boolean before int, because int is also
a valid boolean.

Older python versions (< 3.x?) do not support item
assignments with config parser instances. We have
to workaround therefore.

We can build a sensible list of config file locations on-the-fly.

Right now we consider a file ".diceware" in the users home as
only valid place for a diceware config file.

Only return path if it exists and is valid.

Activates the -w option. Turns out we still have to fix
`get_wordlist_path` at it assumes that wordlists all end in
``.txt`` (which is not true).

The last hotfix to make sys.stdin seek()-able was far from being
proper. It checked only for sys.stdin (which is only one possible
stream delivering unseekable file positions) and didn't consider that
sys.stdin could be replaced (by somthing with proper seek
functionality).

We now test properly for working seek() functionality. If the stream
does not support it, we copy streamdata to a new temporary file. If
the file is not too large, we keep the file data in memory (up to 20
MB), so in most cases runtime trade-off should be moderate.

Input from sys.stdin is valid but not seekable. Cope with that.

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.