Switch contiki to branch 'qidevices'

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Add main .gitignore file

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
rdc: duplicate packets: Keep only the last sequence number for each address

According to IEEE 802.15.4e (§6.4.3.9), in order to detect duplicate received
MAC-layer frames, only the most recently received frame's sequence number needs
to be stored for each unique device address. Doing so limits the possible false
duplicate packet detections to a single sequence number. This also allows to
keep the last sequence number of more device addresses for the same value of
MAX_SEQNOS.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>