Fix disabled for optgroup options (#152)

Author: tj-shapeways

public/jquery.selectric.js

@@ -447,7 +447,7 @@
             $elm.children().each(function(i) {
               var $elm = $(this);
 
-              optionsGroup.items[i] = _this.getItemData(currIndex, $elm, optionsGroup.groupDisabled);
+              optionsGroup.items[i] = _this.getItemData(currIndex, $elm, optionsGroup.groupDisabled || $elm.prop('disabled'));
 
               _this.lookupItems[currIndex] = optionsGroup.items[i];
 

src/jquery.selectric.js

@@ -430,7 +430,7 @@
             $elm.children().each(function(i) {
               var $elm = $(this);
 
-              optionsGroup.items[i] = _this.getItemData(currIndex, $elm, optionsGroup.groupDisabled);
+              optionsGroup.items[i] = _this.getItemData(currIndex, $elm, optionsGroup.groupDisabled || $elm.prop('disabled'));
 
               _this.lookupItems[currIndex] = optionsGroup.items[i];