Fix border-radius not correctly applying when the bottom points have a value of 0.
Fix border-radius not correctly applying when the bottom points have a value of 0.

Closes #1160, closes #374
References #1130, #1104

nathanntg/dompdf,IvoPereira/dompdf,BrunoDeBarros/dompdf,IvoPereira/dompdf,nathanntg/dompdf,edge-soft/dompdf,dompdf/dompdf,dompdf/dompdf,IvoPereira/dompdf,edge-soft/dompdf,BrunoDeBarros/dompdf