Squashed commit of the following:

commit 4139a326404bc89e64e07939a1d2c04163f79886
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Tue Feb 26 15:50:37 2013 +0100

    Removed translations (will add them again after merge)

commit 81e1535c16ab0c5cfc231a0c11a28ce2fc57dc50
Merge: 12a401f 4a63ae1
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Tue Feb 26 15:14:10 2013 +0100

    Merge branch 'develop' into feature-email-login

commit 12a401f89f9a4deefa95f45f4a66c391d36e056a
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Wed Feb 20 15:46:42 2013 +0100

    Updated migration script

commit da80e1c69b7a548182d0d99d1aaa121c9e484ef8
Merge: 25c1c69 659aed9
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Tue Feb 19 14:17:51 2013 +0100

    Merge branch 'develop' into feature-email-login

    Conflicts:
    	adhocracy/controllers/user.py
    	adhocracy/i18n/de/LC_MESSAGES/adhocracy.mo
    	adhocracy/i18n/de/LC_MESSAGES/adhocracy.po

commit 25c1c692d988169eb5672cb5d8f615ea4290c854
Merge: b6ed12a 3201f0c
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Tue Feb 12 18:18:59 2013 +0100

    Merge branch 'develop' into feature-email-login

    Conflicts:
    	adhocracy/i18n/adhocracy.pot
    	adhocracy/i18n/de/LC_MESSAGES/adhocracy.po

commit b6ed12a0cb0acc7ed1c4f551435fd76d848f8191
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Tue Feb 12 12:40:19 2013 +0100

    UserUpdateForm has to check if new email adress is already in use

commit c573b548c54bdcc8f594411e788f264ddeadd31f
Author: carschroeder <schroeder_carsten@gmx.de>
Date:   Mon Jan 14 14:42:07 2013 +0100

    Added german translations for all new strings in this branch

commit 71de496c0c04b3583da9be6bac72505cb4abc42d
Author: carschroeder <schroeder_carsten@gmx.de>
Date:   Thu Dec 20 18:56:42 2012 +0100

    Fixed details for email login

commit c4760bff6b850a20aa5be32fbaed601f96780bbe
Author: test <test@localhost.(none)>
Date:   Thu Dec 20 18:28:45 2012 +0100

    Database migration script

commit 60f97c8366df0879d64842d0b49115ee108f5899
Author: Philipp Hagemeister <phihag@phihag.de>
Date:   Thu Dec 20 18:20:08 2012 +0100

    Require formencode 1.2.5 for <input type=email>

commit 929f3c05cfa5168cec6568c65d59ee9b33844295
Author: Philipp Hagemeister <phihag@phihag.de>
Date:   Thu Dec 6 23:38:10 2012 +0100

    Patch InstanceGroupSourceAdapter._get_item_as_row

commit 321aabc108a84107a1259c3fc4c480211a29f5a4
Merge: 4666373 7bfc7d2
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Thu Dec 20 17:11:20 2012 +0100

    merge

commit 466637399cd96dc21e0a6ebc1ccbdfda0250d3ca
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Mon Dec 10 13:01:32 2012 +0100

    Corrected "failed login" messages depending on allowed login types

commit 562e2d5dba56e7f50554ff0bd2aeda9729a1d352
Merge: 37d6312 122942a
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Thu Dec 6 20:04:45 2012 +0100

    Merge branch 'develop' into feature-email-login

commit 37d63126efc9103eb7856b34479079199724a092
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Thu Dec 6 20:01:26 2012 +0100

    Corrected login_form.html

commit bf6e997e4bee86958365001f43093842e90508e6
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Thu Dec 6 19:32:30 2012 +0100

    Login options added (username+email or only username or only email)

commit 238c960fe9ef26b92e59e0066888c9e14964b87a
Author: Carsten <schroeder_carsten@gmx.de>
Date:   Mon Oct 29 19:05:14 2012 +0100

    login with email or username, not finished
Merge remote-tracking branch 'carschroeder/squash-feature-email-login' into develop
Minor changes for email login
Add doc for login type