Spinner fixes (#1371)

* Fix for function node invalid spinner values

to close #1370

* better validation of spinners for inject and delay

(don’t allow negative numbers)

* remove need for declaring local min variable

nodes/core/core/80-function.html

@@ -73,7 +73,13 @@
         oneditprepare: function() {
             var that = this;
             $( "#node-input-outputs" ).spinner({
-                min:1
+                min:1,
+                change: function(event, ui) {
+                    var value = this.value;
+                    if (!value.match(/^\d+$/)) { value = 1;  }
+                    else if (value < this.min) { value = this.min; }
+                    if (value !== this.value) { $(this).spinner("value", value); }
+                }
             });
 
             this.editor = RED.editor.createEditor({