Made UsbPermissionReceiver Public

This is done to facilitate its usage by other activities as
well. This is needed particularly because BroadcastReceiver
is now to be used by NativeUsb activity as well.
Appropriate modifications are done.
One side effect of this is cleaning of JNI headers. The
new headers are sleek and better.

Signed-off-by: Venkatesh Shukla <venkatesh.shukla.eee11@iitbhu.ac.in>