Link """Quality""" Metrics

[vankerkh]

It looks like we need a link quality metric in order to properly set-up a stable mesh. A outline of this logic is:

1. Spend 1 minute on startup broadcasting to gauge relative link quality
2. Save information to file on what links are of acceptable quality
3. On RPL control messages, connect to nodes with lowest rank && acceptable link quality (ie don't connect to a lower rank if it loses 90% of the packets, connect to the slightly higher rank that only loses 20% of the packets).

[vankerkh]

Steps 1 and 2 completed with pull req #4.
Information saved in .cfg. Each healthy link is separated by a newline (Unix style, \n), with the file terminating with two new line characters in a row (\n\n). The config file only specifies which links are considered healthy. It does not rank links in terms of quality whatsoever. Any link that has a LQR greater than or equal to a threshold value is considered healthy.