Fix get_absolute_url for deleted persons.

Fix #845
Fixed #854: IE fix for ckeditor's plugin insertpre:

Removed 'class' attribute to fix viw in IE8+.
Use monospace in insertpre dialog in IE.
Updated German translation file.
Updated CKEditor from 4.1.1 to 4.2.
Fixed #853: Updated django from 1.5.1 to 1.5.2.
Fixed #857: Use jquery plugin 'bsmSelect' for <select multiple> form elements.
Fixed typo in English translation string in djangojs.po.
Fixed #859: New config option to disable paragraph numbering in motion pdf

Default value: disabled
Fixed #858: Removed max value (8) of config field "motion_min_supporters".

Removed supporters signature field in motion pdf to prevent the unused signature fields
which are printed for each required supporters if you have a high minimum supporters number.