Complete documentation overhaul.

docs/usage/_sidebar.md

@@ -0,0 +1,13 @@
+* [Getting Started](../README.md)
+* [Configuration](../configuration/README.md)
+* [Examples](../examples.md)
+* [Screenshots](../screenshots.md)
+* [Troubleshooting](../troubleshooting.md)
+* [Usage](README.md)
+   * [2-way audio](2-way-audio.md)
+   * [Casting](casting.md)
+   * [URL Actions](url-actions.md)
+
+---
+
+* [Developing](../developing.md)