client: Updating ifup script

- New return codes according to new enums in constant.h
- implementation of ifprobe
- new implementation of ifstatus (ifcheck usage) to see
  the state and/or persistent
client: Add ifstatus alias to show
client: Add --delete and --no-delete options

The --delete options is to delete device (state device-down)
ignoring its configuration or persistent states.
The --no-delete option is not to delete device (state device-exists).
To be used mostly with virtual devices.
client: show: Add status return codes and quiet option

This one is supposed to turn do_show (aka ifstatus) into
something like old ifstatus with --quiet option to be used
from scripts.
Merge pull request #131 from pwieczorkiewicz/merge-18122013-2