Android activity to add a network, and all associated code for dealing

Android activity to add a network, and all associated code for dealing
with WIFI: schemes on the Android side.

 Things to be done:
1. Much more testing.
2. Implement SB and test it well.
3. Clean up the UI to make it beautiful.
4. Figure out what to do when the network is connected: exit the
   Barcode Scanner?  Currently, the activity kills itself, restoring
   camera capture.
5. Publicize the WIFI: scheme.

git-svn-id: http://zxing.googlecode.com/svn/trunk@1425 59b500cc-1b3d-0410-9834-0bbf25fbcc57