Navigation tabs have all been replaced with spinners, because there are no nice
tab libraries for API 9+.

Temporarily hidden because of problems with changing defaults. We don't want to
cause network instability because we have thousands of new unstable routers
churning the network, and can't change their default settings.

In future, we should look at the user's network and settings, and try to have 
"smart" defaults based on a user-chosen profile, or based on net type - see
Connectivity.isConnectionFast().

Android apps should use the client library to connect to I2P Android. The TCP    
interface would only be useful if using the Android device as a gateway or 
dedicated router, but it would need to listen globally, not locally. If someone
asks for that in future, we can add this back and improve the configuration.