This PR works around the changes in how combining-characters are handled in WebKit >= 603 (they are treated as non-combining when there is no character directly preceding them). We include a new single-character font with a non-combining version of this glyph, so all browsers can treat this character the same, and remap U+20D7 to that character when used as an accent. (We have to go through a temporary fake character since REMAPACCENT doesn't allow specifying the variant.)
Resolves issue #1709 (closed).