Added gitignores
Sysfs interface to control Tx queue rate limits

The code is based on:
https://github.com/jrfastab/tx-rate-limits
http://www.linuxplumbersconf.org/2012/wp-content/uploads/2012/09/2012-lpc-Hardware-Rate-Limiting-brandeburg.pdf

To configure the rate limit in Mbps for a queue, edit the file
/sys/class/net/eth1/queues/tx-0/tx_rate_limit