Bbstilson/update documentation for boto3 (#998)

CONTRIBUTING.rst

@@ -9,19 +9,20 @@ Running Tests
 Thanks for your interest in contributing to ``aiobotocore``, there are multiple
 ways and places you can contribute.
 
-Fist of all just clone repository::
+First of all, clone the repository::
 
     $ git clone git@github.com:aio-libs/aiobotocore.git
 
-Create virtualenv with at least python3.5 (older version are not supported).
-For example using *virtualenvwrapper* commands could look like::
+Create virtualenv with at least python3.5 (older versions are not supported).
+For example, using *virtualenvwrapper* commands could look like::
 
    $ cd aiobotocore
    $ mkvirtualenv --python=`which python3.5` aiobotocore
 
 
-After that please install libraries required for development::
+After that, please install libraries required for development::
 
+    $ pipenv lock
     $ pipenv sync --dev
 
 Congratulations, you are ready to run the test suite::

README.rst

@@ -228,11 +228,15 @@ Requirements
 .. _pyright: https://github.com/microsoft/pyright
 .. _mypy: http://mypy-lang.org/
 
-awscli
-------
+awscli & boto3
+--------------
 
-awscli depends on a single version of botocore, however aiobotocore only supports a
-specific range of botocore versions. To ensure you install the latest version of
-awscli that your specific combination or aiobotocore and botocore can support use::
+awscli and boto3 depend on a single version, or a narrow range of versions, of botocore.
+However, aiobotocore only supports a specific range of botocore versions. To ensure you
+install the latest version of awscli and boto3 that your specific combination or
+aiobotocore and botocore can support use::
 
-    pip install -U aiobotocore[awscli]
+    pip install -U 'aiobotocore[awscli,boto3]'
+
+If you only need awscli and not boto3 (or vice versa) you can just install one extra or
+the other.