http://www.unicode.org/charts/
They are classified as PUNCT, which is historically used for characters other
than blank, alphabetic, or digit ones.
Glyph widths are taken from "East Asian Width":
https://www.unicode.org/Public/10.0.0/ucd/EastAsianWidth.txt
Characters of "F" or "W" are classified to SWIDTH2, and others are classified
to SWIDTH1, as implicitly done in the previous revisions.
Should address problems like PR bin/53323.
Discussed with soda@. We thank Takuya SHIOZAKI (tshiozak@) for useful comments.