'Method to build the PDF document.
The response headers are set up for a pdf document and the document
is then sent
@return the document as a stream of characters
@todo add a proper template class so that the doc.build is more generic'

def buildDoc(self):

    styleSheet = getSampleStyleSheet()
    self.doc.build(self.content, canvasmaker=canvas.Canvas)
    self.output.seek(0)
    return self.output.read()
