How to create a new portable windows distribution of openslides:
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1.) Follow the openslides installation instructions for windows, but add
    the option "-Z" when executing easy_install e.g.:
      easy_install -Z django django-mptt reportlab pil

2.) in the main directory of the openslides checkout execute:
      python extras/win32-portable/prepare_portable.py


3.) The portable openslides distribution is now ready as a zip in the dist/
    directory