Merge branch 'clip-zoom-scale' of https://github.com/mgold/d3 into 3.5.7

d3.js

@@ -1369,8 +1369,9 @@
       view = {
         x: view.x,
         y: view.y,
-        k: +_
+        k: null
       };
+      scaleTo(+_);
       rescale();
       return zoom;
     };

src/behavior/zoom.js

@@ -93,7 +93,8 @@ d3.behavior.zoom = function() {
 
   zoom.scale = function(_) {
     if (!arguments.length) return view.k;
-    view = {x: view.x, y: view.y, k: +_}; // copy-on-write
+    view = {x: view.x, y: view.y, k: null}; // copy-on-write
+    scaleTo(+_);
     rescale();
     return zoom;
   };