Add README instructions for using JAR files from Stetho's build system

Without Maven repository support, the integration steps are a little
more involved, requiring developers to build the artifacts locally and
copy/rename them into their project's `libs/` directory.  It is also
required to reference `commons-cli` manually because there is no
dependency resolution when dealing with jar files.

This can be simplified greatly once the project is fully open by
uploading artifacts to Maven central or BinTray's jcenter.

README.md

@@ -34,6 +34,34 @@ easily create your own!
 ![dumpapp prefs Screenshot](https://github.com/facebook/stetho/raw/master/docs/images/dumpapp-prefs.png)
 
 ## Integration
+
+### Add library code
+Assemble the JAR files locally using:
+
+```shell
+./gradlew assemble
+```
+
+Copy the relevant jar files to your `libs/` directory.  Only the main `stetho`
+jar file is strictly required, however you may wish to copy
+`stetho-urlconnection` or `stetho-okhttp` for simplified network integration.
+Also take note that you will need to rename the jar files to avoid conflicts.
+The jar files are located in their respective `build` directories:
+
+```shell
+./stetho/build/intermediates/bundles/debug/classes.jar
+./stetho-urlconnection/build/intermediates/bundles/debug/classes.jar
+./stetho-okhttp/build/intermediates/bundles/debug/classes.jar
+```
+
+You will also need Apache's `commons-cli` library, which you can access from
+`build.gradle`:
+
+```groovy
+compile 'commons-cli:commons-cli:1.2'
+```
+
+### Set-up
 Integrating with Stetho is intended to be seamless and straightforward for
 most existing Android applications.  There is a simple initialization step
 which occurs in your `Application` class: