Merged r6441 from trunk.
PDF: remove unused vendor/plugins/rfpdf/lib/barcode/*.
Merged r6435 from trunk.
PDF: remove unused sjis.rb.
PDF: remove unused vendor/plugins/rfpdf/lib/barcode/* (#8892).
Merged r6434 from trunk.
PDF: remove unused zapfdingbats.rb.
Merged r6433 from trunk.
PDF: remove unused symbol.rb.
Merged r6432 from trunk.
PDF: remove unused courier.rb.
Merged r6431 from trunk.
PDF: remove unused times*.rb.
Merged r6430 from trunk.
PDF: remove unused vera*.rb.
PDF: remove unused sjis.rb (#8892).
PDF: remove unused zapfdingbats.rb (#8892).