Add a SUSE-only crowbar_register utility

This can be used to register a node that was not installed by Crowbar.

This is SUSE-only as support for other OS would probably need some
slight changes to the script to really work. But it should be possible
to do that, provided someone wants to do it.
crowbar_register: Generate addrepo commands with the right URLs

We were hard-coding URLs before, now it should be correct.
crowbar_register: Ask for confirmation before altering the system

There is a new --force argument to skip this step.
Add Support for Xen Virtual Disks (/dev/xvd*)
Merge pull request #249 from vuntz/xvd-disks

Add Support for Xen Virtual Disks (/dev/xvd*)
Merge pull request #238 from vuntz/crowbar_register

Add a SUSE-only crowbar_register utility
Drop executable bits on files
Merge pull request #254 from vuntz/no+x

Drop executable bits on files
Make sure that all nodes always have the correct repos defined

This is a SUSE-only change.
Use --non-interactive with zypper commands
Move duplicated code to a library
Pass --refresh to "zypper addrepo"
Merge pull request #255 from vuntz/enforce-repos

Make sure that all nodes always have the correct repos defined
Revert "enable kernel output on serial console"

This reverts commit 690fad428a59bcf7601a45c3d294cbc733c50deb,
there is already a config option to do that.
Expose serial console attribute via UI

This also changes back the default to "false",
which works around
https://bugzilla.novell.com/show_bug.cgi?id=860088
Make the tty configurable

Depending on your hardware, common serial consoles could be connected
to ttyS0 or ttyS1. Make it configurable in the proposal (hidden
expert setting)
Merge pull request #256 from dirkmueller/release/roxy/master

Rework serial console settings on node
Add UI to set the serial console device
Merge pull request #257 from vuntz/console-ui

Add UI to set the serial console device
Make crowbar_join start after libvirtd and xend

Should help with https://bugzilla.novell.com/show_bug.cgi?id=861030