Final testing update. All functions/classes/methods work as expected.
Will now merge testing with main, after this testing commit.

The following tests were made:

broadcast packets (sent / received / tx status looked for)
unicast packets (sent / received / tx status looked for)
AT-ND packet
Neighbor found & functionality of xbeeNeighbor class

After this test, the code is considered basically ready for large file stream
testing.