[search] remove Bing support

It barely works: outputs unnecessarily long links which are never relevant to what you're looking for.
Also, nobody uses bing apart from Microsoft employees (and they only do so because company policy forces them to do so)

search.py

@@ -119,30 +119,8 @@ def bing_search(query, lang='en-GB'):
     if m:
         return m.group(1)
 
-
-def bing(bot, trigger):
-    """Queries Bing for the specified input."""
-    query = trigger.group(2)
-    if query.startswith(':'):
-        lang, query = query.split(' ', 1)
-        lang = lang[1:]
-    else:
-        lang = 'en-GB'
-    if not query:
-        return bot.reply('.bing what?')
-
-    uri = bing_search(query, lang)
-    if uri:
-        bot.reply(uri)
-        bot.memory['last_seen_url'][trigger.sender] = uri
-    else:
-        bot.reply("No results found for '%s'." % query)
-bing.commands = ['bing']
-bing.example = '.bing swhack'
-
 r_duck = re.compile(r'nofollow" class="[^"]+" href="(.*?)">')
 
-
 def duck_search(query):
     query = query.replace('!', '')
     query = web.quote(query)