updated changelog

Author: chrissimpkins

CHANGELOG.md

@@ -30,6 +30,7 @@
 - U+0078, simplified and improved contours, all variants
 - U+0079, simplified and improved contours, all variants
 - U+007A, simplified and improved contours, all variants
+- added ttdiff.sh shell script for OT table diffs of ttx XML dumps of font binaries
 - ttfautohint-build.sh, fixed backtick and expr syntax shellcheck warnings (SC2003/2006)
 - converted to Semaphore CI (from Travis CI) as CI testing service, eliminated .travis.yml settings file