New modules for grapheme cluster breaking. New module 'unigbrk/base'. * modules/unigbrk/base: New file. * lib/unigbrk.in.h: New file. New module 'unigbrk/uc-gbrk-prop'. * lib/gen-uni-tables.c: Generate lib/unigbrk/gbrkprop.h. * modules/unigbrk/uc-gbrk-prop: New file. * lib/unigbrk/gbrkprop.h: New file. * lib/unigbrk/uc-gbrk-prop.c: New file. New module 'unigbrk/uc-is-grapheme-break'. * modules/unigbrk/uc-is-grapheme-break: New file. * modules/unigbrk/uc-is-grapheme-break-tests: New file. * lib/unigbrk/uc-is-grapheme-break.c: New file. * tests/unigbrk/test-uc-is-grapheme-break.c: New file. * tests/unigbrk/test-uc-is-grapheme-break.sh: New file. * tests/unigbrk/GraphemeBreakTest.txt: New file. With corrections and tweaks by Bruno Haible <bruno@clisp.org>.