Issue #290 gives an example of a wiki with protected pages whose
protection definitions have no 'expiry' key at all. This seems
strange and, on a quick through the mediawiki code, difficult
to achieve, but since there's a live site out there that does it,
and mediawiki *does* seem to have at least some code to handle
such cases (e.g. how the expiry shows as 'indefinite' in the
page information), let's handle it too, by representing this as
None.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

It seems that pytest-cov does not collect any coverage without
this file.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

`clientlogin()` does `self.require(1, 27)`, which needs the site
instance's `version` attribute to be set, but this is usually
done by `site_init()`, which is mocked out in the tests. We can
fix the problem by just manually setting a sufficiently high
version in the tests.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

Allow specifying `uselang` with `Page.revisions()` and
`Site.usercontributions()` to get localized parsed comments with
`prop=parsedcomment`.

Breaking change: Change the `Site.ask()` method to produce less nested
output. Basically, change `yield {title: answer}` to `yield answer`. The
title is included in the answer object after all.

The rvexpandtemplates parameter has been removed, but we can use
action=expandtemplates instead.

This fixes tests not being added to the source package.