fix(fillRect): use height to draw height of rect (#4)

Author: bertyhell

lib/canvasContext.js

@@ -349,8 +349,8 @@ CanvasContext.prototype._fillRect = function CanvasContext__fillRect(fillColor,
     var points = [
         this._transform.multiplyPoint(x, y),
         this._transform.multiplyPoint(x + width, y),
-        this._transform.multiplyPoint(x + width, y + width),
-        this._transform.multiplyPoint(x, y + width),
+        this._transform.multiplyPoint(x + width, y + height),
+        this._transform.multiplyPoint(x, y + height),
         this._transform.multiplyPoint(x, y)
     ];