add scripts/pyment executable
do not write description on first line if docstring is on several lines
count number of spaces on the first declaration line

It prevent bugs when a function is defined for example like that:

    def open(self, url, referrer=None,
                   allow_redirects=True,
                   stream=None,
                   timeout=None,
                   verify=None,
                   cert=None,
                   proxies=None,
                   **kwargs):
        """
        Make an HTTP request like a browser does:
        ...
        """

Because as the last line in "                   **kwargs):", it doesn't match
regexp and the spaces count is 0.