Adding initialization code
++++++++++++++++++++++++++++
What about adding environment variables for gis env.
::

    >>> init_env()
    >>> index_url = start_server(os.path.sep.join(tempdir))   
    >>> data = """
    ... [buildout]
    ... eggs-directory =${buildout:directory}/eggs
    ... download-cache=${buildout:directory}/dl
    ... parts = part
    ... [part]
    ... recipe=minitage.recipe.scripts
    ... find-links=%(index)s
    ... entry-points=t=toto.toto:f
    ... eggs=foo
    ... initialization = import os;os.environ.set('GDAL', 'TRUE')
    ... """%{'index': index_url}
    >>> touch('buildout.cfg', data=data)
    >>> sh('bin/buildout -vvvvv install')
    b...

::

    >>> "import os;os.environ.set('GDAL', 'TRUE')" in open(os.path.join('bin', 't')).read()
    True


