scripts: update-oui: Add OUI list update script

Instead of having to maually update the oui.conf file used by
netsniff-ng to resolve OUIs to vendor names, provide a script which
fetches the necessary information from any file in the format as
provided by the IEEE at
http://standards.ieee.org/develop/regauth/oui/oui.txt

This is also the default URL the script will fetch the information from.

The script runs with Python 2.x and 3.x and only uses the respective
standard libraries.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
conf: Update oui.conf using scripts/update-oui.py

Update created using the command inside the netsniff-ng source tree:

$ ./scripts/update-oui.py -f -o src/conf/oui.conf
Updating OUI information in src/conf/oui.conf from http://standards.ieee.org/develop/regauth/oui/oui.txt...
17315 OUIs written to src/conf/oui.conf

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Merge branch 'oui' of git://github.com/tklauser/netsniff-ng