title: pip install icalendar: pytz not found
body: <p>I try to install icalendar on our local pypi server:</p>
  
  <p>The first attempt failed, now I know that I need to use --pre for pytz. But nevertheless the dependency can't be found:</p>
  
  <pre><code>(pypi)pypi@gray:~&gt; pip install --pre  -d packages  pytz
  Downloading/unpacking pytz
    Downloading pytz-2013d.tar.bz2 (204kB): 204kB downloaded
  Saved ./packages/pytz-2013d.tar.bz2
  Running setup.py egg_info for package pytz
  
    warning: no files found matching '*.pot' under directory 'pytz'
    warning: no previously-included files found matching 'test_zdump.py'
  Successfully downloaded pytz
  Cleaning up...
  </code></pre>
  
  <p>Now I try to install icalendar:</p>
  
  <pre><code>(pypi)pypi@gray:~&gt; pip install -d packages icalendar
  Downloading/unpacking icalendar
    File was already downloaded packages/icalendar-3.5.tar.gz
    Running setup.py egg_info for package icalendar
  
      warning: no previously-included files matching '*.pyc' found under directory 'src/icalendar'
  Downloading/unpacking setuptools (from icalendar)
    File was already downloaded packages/setuptools-1.1.5.tar.gz
    Running setup.py egg_info for package setuptools
  
  Downloading/unpacking python-dateutil (from icalendar)
    File was already downloaded packages/python-dateutil-2.1.tar.gz
    Running setup.py egg_info for package python-dateutil
  
  Downloading/unpacking pytz (from icalendar)
    Could not find a version that satisfies the requirement pytz (from icalendar) (from versions: 2010b, 2012f, 2010e, 2005m, 2011e, 2010l, 2010e, 2009u, 2008c, 2006j,... 2013d, 2013d, 2012h, 2011h, 2013b, 2012d, 2004b)
  Cleaning up...
  No distributions matching the version for pytz (from icalendar)
  Storing complete log in /home/pypi/.pip/pip.log
  </code></pre>
  
  <p>Any hint how to solve this?</p>