font/sfnt: support post table version 1.0
font/sfnt: support post table version 1.0

Currently, the library produces a parsing error when the font
contains a PostScript table of version 1.0.

CL adds this version to the validation code and implements a glyph
name lookup for it.

Change-Id: Id4999d8b252e5c2d8e897f637ba31270336cfe9a
Reviewed-on: https://go-review.googlesource.com/c/146080
Reviewed-by: Nigel Tao <58ae08b3356928ff9c67562b4719487d54fe8348@golang.org>

golang/image