This name is unused on pypi. Let's grab it.

Instead of generating the list of message ids anew during every build,
the file is generated manually and committed into the
repository. Also, the list of defines is stored in id128-defines.h,
also kept in the repository. Both files should only grow.

This should make build easier. But it also fixes a problem with
systemd, which occasionally drops message definitions. We will keep
them forever, so it should be safe to rely on the presence of message
definitions which systemd does not use anymore.

Fixes #23.

This somewhat breaks backwards compatibility, but not for the
previously documented arguments: floats are now interpreted
differently, but ints and datetime.datetime objects are interpreted
the same as before. But the documentation clearly stated that only
ints and datetime.datetime objects were allowed.

This makes seek_realtime match seek_monotonic and other functions
which take time and follows the principle of least surprise.

Fixes #21.

Let's pass any flags through to the journal functions without checking
validity. Those functions do their own checking, so there's no need to
second-guess.

The semantics for _Reader(flags=0) are a bit changed:
before, this would be transformed into sd_journal_open(SD_J_LOCAL_ONLY).
Now, this results in sd_journal_open(0). Previous behaviour should be
achieved by not specifying the flags at all.
This change is necessary, because previously it was not possible to
pass flags=0 to sd_journal_open(0), i.e. it was not possible to "merge"
journals through the Python interface.

Similarly, Reader(flags=0) now means to open all journals, and
Reader(flags=None) is the same as Reader(flags=LOCAL_ONLY).

Those are field names and they should always be ASCII, and converting
them to str automatically makes the answer more useful.