Will finish in morning.

Will revise all permissions code eventually when adopting the
permissions.db system.

Allow a normal user to devoice and deop themselves

Some wikis (like frwiki), set their projects to localized forms of
the expected (so "wikipedia" becomes "wikipédia"). An additional
search by URL in _get_site_name_from_sitesdb() fixes this.

* Apparently bool(cookiejar) is False if the cookiejar doesn't
contain any cookies, even if it exists. Change `if cookiejar` to
`if cookiejar is not None` to get around this.