parse_color: recognize "no$foo" to clear the $foo attribute

diff --git a/RelNotes b/RelNotes
index 8c65931ff4d966ea7c76cdfa1fcb000c97ab1c19..192f48cc9470b11e01edda4f0a84a257480ca96c 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/1.7.3.txt
\ No newline at end of file
+Documentation/RelNotes/2.1.3.txt
\ No newline at end of file