Korean Character Widths

Hi,

Anyone here up to snuff on their Korean and willing to review some 
character width adjustments in our localedata?

https://reviews.freebsd.org/D47472 adds a number of zero-width 
exceptions for characters that are reportedly expected to be treated as 
combining characters (Hangul Jamo medial vowels and final consonants in 
the U+1160 - U+11FF range.  A sanity check on this would be quite 
welcome; they had referred me to a wcwidth implementation by Markus Kuhn 
as a point of reference:

https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c

Thanks,

Kyle Evans