Headers
-------

As you can see, the `contents` of the browser does not return any HTTP
headers.  The headers are accessible via a separate attribute, which is an
``httplib.HTTPMessage`` instance (httplib is a part of Python's standard
library):

    >>> browser.base = 'http://localhost:%s/' % TEST_PORT
    >>> browser.open('index.html')
    >>> browser.headers
    <httplib.HTTPMessage instance...>

The headers can be accessed as a string:

    >>> print browser.headers
    Server: BaseHTTP
    Date: Mon, 17 Sep 2007 10:05:42 GMT
    Connection: close
    Content-type: text/html

Or as a mapping:

    >>> browser.headers['content-type']
    'text/html'
