Use GET rather than POST for allpages API query

POST does not follow the redirect from HTTP to HTTPS, which makes the
request (and the entire dump) fail if an API URL is passed like
http://7daystodie-de.gamepedia.com/api.php

Fixes https://github.com/WikiTeam/wikiteam/issues/334

dumpgenerator.py

@@ -271,7 +271,7 @@ def getPageTitlesAPI(config={}, session=None):
             retryCount = 0
             while retryCount < config["retries"]:
                 try:
-                    r = session.post(url=config['api'], data=params, timeout=30)
+                    r = session.get(url=config['api'], params=params, timeout=30)
                     break
                 except ConnectionError as err:
                     print "Connection error: %s" % (str(err),)