Fixes writing frames to a pcap file.

The writing of frames to a pcap was incorrect and always returned an
error. This was caused by the size of a write call being incorrectly
checked with the size of data in bits instead of bytes.
Removes obsolete code from the injector.

The addressing mechanism used in the injector is now obsolete. We use
the mac parsing function to decode parameters instead.
Fixes the decoding of frames without payload.

When a frame contained an empty payload, the mac decoding function would
parse an element of negative size. This case is normally captured and
the payload is set to NULL. However this negative size was converted to an
unsigned int and taken into account for the frame size check. This
resulted in an incorrect frame size and an error from the mac decode
function.
Fixes long addresses interpreted as fully compressed addresses.

When an user entered a long address, the associated address mode was set
to FULL, that is a fully compressed address instead of a long
address. This resulted in incorrectly parsed and encoded frames.
Adds examples of 6LoWPAN payloads.

This adds examples of 6LoWPAN-ND and PING payloads. These examples are
sufficient to simulate a full ping from a fake injector to a real host.