confine turtle direction readout to 0-360 degrees

addresses a bug report from Cynthia Solomon

history.txt

@@ -3509,6 +3509,7 @@ Fixes:
 ------
 * Objects, GUI, Store: tweak naming of instantiating to “clone”, enable inheritance by default
 * Objects, GUI: run “When I start as clone” scripts when manually cloning a sprite, only position at hand pointer if no such scripts exist 
+* Morphic, Objects: confine turtle direction readout to 0-360 degrees, thanks, Cynthia for the bug report!!
 
 
 Features:

morphic.js

@@ -1161,7 +1161,7 @@
 
 /*global window, HTMLCanvasElement, FileReader, Audio, FileList*/
 
-var morphicVersion = '2017-July-04';
+var morphicVersion = '2017-July-07';
 var modules = {}; // keep track of additional loaded modules
 var useBlurredShadows = getBlurredShadowSupport(); // check for Chrome-bug
 
@@ -4838,7 +4838,7 @@ PenMorph.prototype.drawNew = function (facing) {
 // PenMorph access:
 
 PenMorph.prototype.setHeading = function (degrees) {
-    this.heading = parseFloat(degrees) % 360;
+    this.heading = ((+degrees % 360) + 360) % 360;
     this.drawNew();
     this.changed();
 };

objects.js

@@ -4262,7 +4262,7 @@ SpriteMorph.prototype.setHeading = function (degrees, noShadow) {
         this.silentGotoXY(x, y, true); // just me
         this.positionTalkBubble();
     } else {
-        this.heading = parseFloat(degrees) % 360;
+        this.heading = ((+degrees % 360) + 360) % 360;
     }
 
     // propagate to my parts