This updates the svg, png, and html resources from behdad/region-flags.
It also updates the LICENSE (COPYING) and README.md files from there.
Formerly our copy contained only a few subregion flags, but this change
adds them all from upstream.
Also formerly we explicitly used symlinks in our data for flags that
are the same as other country flags. Now however we just use the
upstream data. Note that the emoji_aliases.txt file will still
cause the font to only have one copy of these.
Note this also deletes the copy of IC.png that somehow had found its
way into the region-flags directory.
Use big glyph metrics to support vertical text rendering
Qingqing Deng