Restructure contrib_bots bots to new layout.

In order to make the layout of all bots consistent, this commit
moves each bot into a folder with its name and modifies 'run.py'
so that only bots with such a structure can be executed. 'lib'
gets renamed to 'bots'.

contrib_bots/bots/john/john.py

@@ -0,0 +1,131 @@
+import json
+import os
+import sys
+
+from random import choice
+
+try:
+    from chatterbot import ChatBot
+    from chatterbot.trainers import ChatterBotCorpusTrainer, ListTrainer
+except ImportError:
+    raise ImportError("""It looks like you are missing chatterbot.
+                      Please: pip install chatterbot""")
+
+CONTRIB_BOTS_DIR = os.path.dirname(os.path.abspath(__file__))
+os.chdir(os.path.dirname(CONTRIB_BOTS_DIR))
+sys.path.insert(0, os.path.dirname(CONTRIB_BOTS_DIR))
+
+JOKES_PATH = os.path.join(CONTRIB_BOTS_DIR, 'John/var/jokes.json')
+DATABASE_PATH = os.path.join(CONTRIB_BOTS_DIR, 'John/var/database.db')
+DIRECTORY_PATH = os.path.join(CONTRIB_BOTS_DIR, 'John')
+VAR_PATH = os.path.join(CONTRIB_BOTS_DIR, 'John/var')
+
+if not os.path.exists(DIRECTORY_PATH):
+    os.makedirs(DIRECTORY_PATH)
+
+if not os.path.exists(VAR_PATH):
+    os.makedirs(VAR_PATH)
+
+# Create a new instance of a ChatBot
+def create_chat_bot(no_learn):
+    return ChatBot("John",
+                   storage_adapter="chatterbot.storage.JsonFileStorageAdapter",
+                   logic_adapters=
+                   [
+                      "chatterbot.logic.MathematicalEvaluation",
+                      {
+                          "import_path": "chatterbot.logic.BestMatch",
+                          "response_selection_method": "chatterbot.response_selection.get_random_response",
+                          "statement_comparison_function": "chatterbot.comparisons.levenshtein_distance"
+                      }],
+                   output_adapter="chatterbot.output.OutputFormatAdapter",
+                   output_format='text',
+                   database=DATABASE_PATH,
+                   silence_performance_warning="True",
+                   read_only=no_learn)
+
+bot = create_chat_bot(False)
+bot.set_trainer(ListTrainer)
+
+bot.train([
+    "I want to contribute",
+    """Contributors are more than welcomed! Please read
+    https://github.com/zulip/zulip#how-to-get-involved-with-contributing-to-zulip
+    to learn how to contribute.""",
+])
+
+bot.train([
+    "What is Zulip?",
+    """Zulip is a powerful, open source group chat application. Written in Python
+    and using the Django framework, Zulip supports both private messaging and group
+    chats via conversation streams. You can learn more about the product and its
+    features at https://www.zulip.org.""",
+])
+
+bot.train([
+    "I would like to request a remote dev instance",
+    """Greetings! You should receive a response from one of our mentors soon.
+    In the meantime, why don't you learn more about running Zulip on a development
+    environment? https://zulip.readthedocs.io/en/latest/using-dev-environment.html""",
+])
+
+bot.train([
+    "Joke!",
+    "Only if you ask nicely!",
+])
+
+bot.train([
+    "What is your name?",
+    "I am John, my job is to assist you with Zulip.",
+])
+
+bot.train([
+    "What can you do?",
+    "I can provide useful information and jokes if you follow etiquette.",
+])
+
+with open(JOKES_PATH) as data_file:
+    for joke in json.load(data_file):
+        bot.train([
+            "Please can you tell me a joke?",
+            joke['joke'],
+        ])
+
+bot.set_trainer(ChatterBotCorpusTrainer)
+
+bot.train(
+    "chatterbot.corpus.english"
+)
+
+bota = create_chat_bot(True)
+
+class JohnHandler(object):
+    '''
+    This bot aims to be Zulip's virtual assistant. It
+    finds the best match from a certain input.
+    Also understands the English language and can
+    mantain a conversation, joke and give useful information.
+    '''
+
+    def usage(self):
+        return '''
+            Before running this, make sure to create a stream
+            called "VirtualHelp" that your API user can send to.
+            '''
+
+    def triage_message(self, message, client):
+        original_content = message['content'].lower()
+        return (original_content.startswith("@john") or
+                original_content.startswith("@**john**"))
+
+    def handle_message(self, message, client, state_handler):
+        original_content = message['content']
+        client.send_message(dict(
+            type='stream',
+            to='VirtualHelp',
+            subject="John",
+            content=bota.get_response(original_content)
+        ))
+
+handler_class = JohnHandler
+