Change overlay_frame payload to use an overlay_buffer structure for
consistency and ease of payload construction.
Added some sanity checking to peer score calculation.
Getting closer to being able to TX acks to selfannouncements.
Other little things to accomplish these.
which is now used for both encapsulation and decapsulation.
Improved payload length encoding scheme to be shorter for most payload
lengths.
selfannouncement frames now get directed to stub functions for
implementation.
