vg/vgpdf: migrate to jung-kurt/gofpdf
This CL drops bitbucket/zombiezen/gopdf/pdf in favour of github.com/jung-kurt/gofpdf.
Fixes #389 (closed).
This CL drops bitbucket/zombiezen/gopdf/pdf in favour of github.com/jung-kurt/gofpdf.
Fixes #389 (closed).