bots: Clean up terminal.py for running bots directly.

Make terminal.py exit gracefully with a message.
Modify output bot reply for better understanding in multi-line
output.

zulip_bots/zulip_bots/simple_lib.py

@@ -1,4 +1,5 @@
 import configparser
+import sys
 
 class SimpleStorage:
     def __init__(self):
@@ -49,10 +50,7 @@ class TerminalBotHandler:
         return self.message_server.send(message)
 
     def send_reply(self, message, response):
-        print('''
+        print("\nReply from the bot is printed between the dotted lines:\n-------\n{}\n-------".format(response))
-            reply:
-            {}
-            '''.format(response))
         response_message = dict(
             content=response
         )

zulip_bots/zulip_bots/terminal.py

@@ -56,6 +56,7 @@ def main():
 
     sender_email = 'foo_sender@zulip.com'
 
+    try:
         while True:
             content = input('Enter your message: ')
 
@@ -68,6 +69,10 @@ def main():
                 message=message,
                 bot_handler=bot_handler,
             )
+    except KeyboardException:
+        print("\n\nOk, if you're happy with your terminal-based testing, try it out with a Zulip server.",
+              "\nYou can refer to https://zulipchat.com/api/running-bots#running-a-bot.")
+        sys.exit(1)
 
 if __name__ == '__main__':
     main()