Introduce "slapos node register" script.

Squashed commit of the following:

commit a9aa690c5b74de55fed2499cbe6a2a205fbc2550
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Fri Aug 17 10:18:14 2012 +0200

    Introduce use of logger

commit a36d37f766062eb5faed1e179d64a6c6a2bc2e50
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 16 19:05:09 2012 +0200

    update copyright from 2010 to 2012

commit 167c2a83d45a5e1ca88dab806a5612e981aaf6a9
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 16 19:02:56 2012 +0200

    Add dry run control in saving old configuration

commit 80eecf880c214c96d780547e95c447d794a87c0e
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 16 19:00:35 2012 +0200

    Clean code

commit 359cf29263e72f2070659d7fdc1ba227dff85426
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 16 18:51:43 2012 +0200

    Moved comments to docs

commit 84077e2a926b7d8fdf2495001df9378a301b5bbd
Merge: 42f2b2d 8d7ba61
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 16 18:46:52 2012 +0200

    Merge remote-tracking branch 'origin/register' into register

commit 42f2b2dae626dfa7ef54f2df97e21d089e5890d7
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 16 18:46:31 2012 +0200

    Moved register.py to register/

commit 8d7ba617c3d0697683eff48aee8401067d23c413
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 16 10:48:48 2012 +0200

    Display error if wrong usage

commit 927d395f2f3e1f01085c38ea681f16034182e2bd
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Tue Aug 14 14:57:33 2012 +0200

    Added created_tap = false in slapos.cfg

commit 49669afd0514f01b4720f94137c1f76cc47b4904
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Tue Aug 14 12:05:07 2012 +0200

    If a slapos.old file is find, backup will be made in slapos.old.i
    Where i is the lower integer available starting at 1

commit 430406f39753af3f2de26e5a631350c5fb997a3a
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Tue Aug 14 11:04:11 2012 +0200

    Can pass login and password in command line argument

commit 50b19497981d274f327fbe44c619a221539697aa
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 9 11:49:29 2012 +0200

    Solved bug in writting interface in slapos.cfg

commit 27fe79c859a65095493303da7f81ace0c3643641
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 9 10:51:10 2012 +0200

    Added option to modify master webservice url for computer registration

commit 9ed75848324789bb01404592780ba7cd2ab65f3c
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 9 10:17:28 2012 +0200

    Removed useless recursive include in MANIFEST.in

commit 6b2d90c0b8149872b56dc9b565cb4800c3183594
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 9 10:08:31 2012 +0200

    removed useless parameters in Option function call

commit 34083f2351570a1413bffb18db05bd17a6a8a18c
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 9 10:06:07 2012 +0200

    removed useless '/'.join in os.path.join

commit 8408a213e655cc9030493d8a4695a4e4c0380c30
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Thu Aug 9 09:53:07 2012 +0200

    Withdraw unused module from code

commit 2805cf2a9927e0b09a60984f7255423602e37e31
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Wed Aug 8 16:17:31 2012 +0200

    Fixed forgotten code

commit 35e0b0ba9c6a7a9782a895b7ff74ab1294d1cad2
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Wed Aug 8 15:53:50 2012 +0200

    Added slapos entry point, just giving acces to register script now

commit d2456a5a5f9135176498ac40088850627e21f88c
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Wed Aug 8 11:46:34 2012 +0200

    Register function is now made to run in command line
    ipv6 interface option added

commit 71bc5c9edae00502cf09abaac4a4d70be96d4a9a
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Tue Aug 7 17:40:56 2012 +0200

    Added creation partition_pki repertory

commit e80fede661858f98d0508bf61c4489b2e174882e
Author: Cédric Le Ninivin <cedric.leninivin@tiolive.com>
Date:   Tue Aug 7 17:01:23 2012 +0200

    Introducing independant register function that saves configuration in /etc/opt/slapos/slapos.cfg