update instructions (rm-hull#110)

* update instructions

* fix tweet_scroll example (for Python 3.7)

`async` is a reserved keyword.

Author: thijstriemstra

README.rst

@@ -41,7 +41,8 @@ Running the examples
 After cloning the repository, enter the ``examples`` directory and try running
 one of the following examples listed below. For example::
 
-  python examples/3d_box.py
+  cd examples
+  python 3d_box.py
 
 ========================= ================================================================
 Example                   Description

examples/tweet_scroll.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-# Copyright (c) 2014-18 Richard Hull and contributors
+# Copyright (c) 2014-2020 Richard Hull and contributors
 # See LICENSE.rst for details.
 # PYTHON_ARGCOMPLETE_OK
 
@@ -107,7 +107,7 @@ def on_status(self, status):
 
 try:
     stream = tweepy.Stream(auth=api.auth, listener=listener(queue))
-    stream.filter(track=search_terms, async=True)  # noqa: W606
+    stream.filter(track=search_terms, is_async=True)  # noqa: W606
 
     try:
         while True: