Remove "downscale only" mode

The normal scaling mode should be sufficient for most use cases, so
let's keep the interface simple.

core/display.js

@@ -517,7 +517,7 @@ Display.prototype = {
         this._target.style.cursor = "none";
     },
 
-    autoscale: function (containerWidth, containerHeight, downscaleOnly) {
+    autoscale: function (containerWidth, containerHeight) {
         var vp = this._viewportLoc;
         var targetAspectRatio = containerWidth / containerHeight;
         var fbAspectRatio = vp.w / vp.h;
@@ -529,10 +529,6 @@ Display.prototype = {
             scaleRatio = containerHeight / vp.h;
         }
 
-        if (scaleRatio > 1.0 && downscaleOnly) {
-            scaleRatio = 1.0;
-        }
-
         this._rescale(scaleRatio);
     },
 

core/rfb.js

@@ -351,9 +351,9 @@ RFB.prototype = {
         RFB.messages.clientCutText(this._sock, text);
     },
 
-    autoscale: function (width, height, downscaleOnly) {
+    autoscale: function (width, height) {
         if (this._rfb_connection_state !== 'connected') { return; }
-        this._display.autoscale(width, height, downscaleOnly);
+        this._display.autoscale(width, height);
     },
 
     viewportChangeSize: function(width, height) {