updated README

Author: sommersoft

README.rst

@@ -9,7 +9,11 @@ Adafruit CircuitPython BusDevice
     :target: https://adafru.it/discord
     :alt: Discord
 
-The `I2CDevice` and `SPIDevice` helper classes make managing transaction state
+.. image:: https://travis-ci.org/adafruit/Adafruit_CircuitPython_BusDevice.svg?branch=master
+    :target: https://travis-ci.org/adafruit/Adafruit_CircuitPython_BusDevice
+    :alt: Build Status
+
+The ``I2CDevice`` and ``SPIDevice`` helper classes make managing transaction state
 on a bus easy. For example, they manage locking the bus to prevent other
 concurrent access. For SPI devices, it manages the chip select and protocol
 changes such as mode. For I2C, it manages the device address.
@@ -28,9 +32,62 @@ To install:
 #. Download and unzip the `latest release zip <https://github.com/adafruit/Adafruit_CircuitPython_BusDevice/releases>`_.
 #. Copy the unzipped ``adafruit_bus_device`` to the ``lib`` directory on the ``CIRCUITPY`` drive.
 
-API
----
-.. toctree::
-    :maxdepth: 3
+Usage Example
+=============
+
+See examples/read_register_i2c.py and examples/read_register_spi.py for examples of the module's usage.
+
+Contributing
+============
+
+Contributions are welcome! Please read our `Code of Conduct
+<https://github.com/adafruit/Adafruit_CircuitPython_BusDevice/blob/master/CODE_OF_CONDUCT.md>`_
+before contributing to help this project stay welcoming.
+
+Building locally
+================
+
+To build this library locally you'll need to install the
+`circuitpython-build-tools <https://github.com/adafruit/circuitpython-build-tools>`_ package.
+
+.. code-block:: shell
+
+    python3 -m venv .env
+    source .env/bin/activate
+    pip install circuitpython-build-tools
+
+Once installed, make sure you are in the virtual environment:
+
+.. code-block:: shell
+
+    source .env/bin/activate
+
+Then run the build:
+
+.. code-block:: shell
+
+    circuitpython-build-bundles --filename_prefix adafruit-circuitpython-busdevice --library_location .
+
+Sphinx documentation
+-----------------------
+
+Sphinx is used to build the documentation based on rST files and comments in the code. First,
+install dependencies (feel free to reuse the virtual environment from above):
+
+.. code-block:: shell
+
+    python3 -m venv .env
+    source .env/bin/activate
+    pip install Sphinx sphinx-rtd-theme
+
+Now, once you have the virtual environment activated:
+
+.. code-block:: shell
+
+    cd docs
+    sphinx-build -E -W -b html . _build/html
+
+This will output the documentation to ``docs/_build/html``. Open the index.html in your browser to
+view them. It will also (due to -W) error out on any warning like Travis will. This is a good way to
+locally verify it will pass.
 
-    adafruit_bus_device/index