Add utility and .h for character's UTF-8

Add utility and .h for character's UTF-8

This add regen/utf8_strings.pl takes Unicode characters and generates
utf8_strings.h to contains #defines for macros that translate from the
name to the UTF-8.  This is needed in a few places, where previously
things were manually figured out and hard-coded in.  Doing this instead
makes this easier, and removes EBCDIC dependencies/bugs, as the file
would simply be regen'd on an EBCDIC platform.