weblinkchecker should be converted to requests.
The class `LinkChecker` should be deprecated using `@deprecated`, and otherwise not modified. The class `LinkChecker` is too intrinsically tied to `httplib` to be enhanced without causing backwards compatibility bugs.
The function `check` may also be deprecated using `@deprecated`, or rewritten using `requests`.
`LinkCheckThread` needs to be revised, rewriting the first half of method `run` using similar functionality using `requests`.
It only needs to perform a http fetch, which can be done using `pywikibot.comms.http.fetch` or `requests` directly, check the http status code against `HTTPignore`, and then call `self.history` methods as it already does.
It should skip any URL which matches the pattern in `ignorelist`.
To test, use https://en.wikipedia.org/wiki/User:John_Vandenberg/test_T113596
```
$ rm -rf deadlinks/
$ python pwb.py weblinkchecker -family:wikipedia -lang:en -page:User:John_Vandenberg/test_T113596 -day:0 -talk
....
$ python -c "import pickle, pprint; print(pprint.pformat(pickle.loads(open('deadlinks/deadlinks-wikipedia-en.dat').read())))"
{u'http://httpbin.org/basic-auth/user/passwd': [(u'User:John Vandenberg/test T113596',
1453205828.731368,
u'401 UNAUTHORIZED')],
u'http://httpbin.org/status/404': [(u'User:John Vandenberg/test T113596',
1453205828.694601,
u'404 NOT FOUND')],
u'http://httpbin.org/status/410': [(u'User:John Vandenberg/test T113596',
1453205828.74228,
u'410 GONE')],
u'http://www.admi.net/jo/20010615%C2%A6/ECOC0100037D.html': [(u'User:John Vandenberg/test T113596',
1453205828.913141,
u'404 Not Found')],
u'https://self-signed.pythontest.net/': [(u'User:John Vandenberg/test T113596',
1453205828.191287,
u"Socket Error: u'[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:590)'")]}
$ python pwb.py weblinkchecker -family:wikipedia -lang:en -page:User:John_Vandenberg/test_T113596 -day:0 -talk
....
```
This should also post a notice on https://en.wikipedia.org/wiki/User_talk:John_Vandenberg/test_T113596 (blank that page after each test run)
To test deprecation, do
```
$ python pwb.py shell
...
>>> from scripts import weblinkchecker
>>> weblinkchecker.check('http://google.com')
```
It should produce a useful message.