Add docs to Network
Add docs to Network

Still must be hidden until we unhide the new API in ConnectivityManager.

Change-Id: I4749e56777199093cdba9223eb3d721c3174047d

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base