simplified the readme changes for the new root_url config option.
simplified the readme changes for the new root_url config option.

pdfkit/pdfkit,globalxolutions/pdfkit,globalxolutions/pdfkit,asomanescu/pdfkit,gdi2290/pdfkit,ContinuityControl/pdfkit,christhekeele/pdfkit,dimko/pdfkit,asomanescu/pdfkit,centresource/pdfkit,toggl/pdfkit,christhekeele/pdfkit,cdwort/pdfkit