Adding api review changes
Updating listener callbacks names
Updating hello world app with app review changes
Cleaning comments
README description of the Android Hello World app.
some changes to MainActivity.java:
- Changes to comments.
- Removal of API_KEY (which is unused).
- Removal of AUTO_CONNECT and AUTO_PUBLISH (and their use in the code). These don't seem to be too instructive.
- Empty string assignments to the session ID and token string.
- Simplified the subscribeToSelf logic
- Whitespace changes for consistency.