[css-images-3] Update changes list.

Author: tabatkins

css-images-3/Overview.bs

@@ -1798,11 +1798,23 @@ Changes Since the <a href="https://www.w3.org/TR/2012/CR-css3-images-20120417/">
 
 	- The <css>image()</css> notation has been deferred to Level 4.
 	- The <css>image-resolution</css> property has been deferred to Level 4
-	- The 'image-orientation' property has been marked as At-Risk,
-		the ''from-image'' and ''image-orientation/none'' keywords,
-		and the <<angle>> values deprecated.
-	- Added the 'image-rendering' property
-	- Added the ''cross-fade()'' notation
+	- The 'image-orientation' property has been marked as At-Risk. Additionally:
+		- Added the ''from-image'' and ''image-orientation/none'' keywords
+		- Deprecated the <<angle>> values
+		- Added and deprecated the <css>flip</css> values
+	- Added the 'image-rendering' property.
+	- Moved the <<resolution>> type to [[css-values-3]].
+	- Better defined the handling of invalid and partially-loaded images.
+	- Defined the general computed form of <<image>>.
+	- Defined concept and handling of URLs that are ambiguous between being images or element references.
+	- Defined that the unit can be omitted for zero angles in ''linear-gradient()'' due to compat.
+	- Slightly clarified handling of degenerate repeating radial gradients.
+	- Added [=transition hints=] to <<color-stop-list>>,
+		and editorially rewrote section on gradient color stops to better accommodate the new prose.
+	- Added "Canonical Order" and "Animation Type" to all property definition tables.
+	- Defined interpolation and serialization of <<image>> values.
+	- Various minor clarifications.
+
 
 <h3 class=no-num id=changes-last-call>
 Changes Since Last Call</h3>