Fixed #923 by replacing the usage of 'ifconfig' with 'ip a' where appropriate and added a note to use 'ip a' instead of 'ifconfig' for a screencast transscript.
Use the canonical 'ip' commands to make it easier for new 'iproute2' users to understand the usage.
use https repo url to clone for dev setup instructions

the git clone line in the dev setup instructions does not work as is, unless the user has write access
Merge pull request #944 from hansent/patch-1

* Documentation: use https repo url to clone for dev setup instructions
Merge pull request #924 from eliasp/remove-ifconfig-usage

* Documentation: replace `ifconfig` in docs with `iproute`