contrib_bots: Restructure bots to follow a consistent structure.

Now all the bots that are stored in contrib_bots are in the
same file/directory format.
The format is specified here #3427. Add tests.py file for encrypt_bot as well.
Fixes #3427.

contrib_bots/bots/foursquare/foursquare.py

@@ -9,13 +9,13 @@ from six.moves import configparser as cp
 from six.moves import range
 
 home = expanduser('~')
-CONFIG_PATH = home + '/zulip/contrib_bots/bots/foursquare/FourSquareBot/settings.ini'
+CONFIG_PATH = home + '/zulip/contrib_bots/bots/foursquare/foursquare.config'
 
 def get_api_key():
-    # settings.ini must have been moved from
-    # ~/zulip/contrib_bots/bots/foursquare/FourSquareBot/settings.ini into
-    # ~/settings.ini for program to work
-    # see doc.md for more information
+    # foursquare.config must have been moved from
+    # ~/zulip/contrib_bots/bots/foursquare/foursquare.config into
+    # ~/foursquare.config for program to work
+    # see readme.md for more information
     with open(CONFIG_PATH) as settings:
         config = cp.ConfigParser()
         config.readfp(settings)