fix(options): mark options as selected on change of options even if o…

…ptions are objects

Internal Option representation is an object which is created newly on each change of options collection. Array#indexOf with objects compares by reference and not equality. Because of that the option put into ngModel out site are not marked as selected.
By calculating and comparing hash codes of the option the directive is now independent of the kind of options.

Closes #7

src/w11k-select.js

@@ -458,20 +458,25 @@ angular.module('w11k.select').directive('w11kSelect', [
         var optionsExpParsed = optionParser.parse(optionsExp);
 
         function collection2options(collection, viewValue) {
+          var viewValueHashes = viewValue.map(function (selectedValue) {
+            return hashCode(selectedValue);
+          });
+
           return collection.map(function (option) {
             var optionValue = modelElement2value(option);
+            var optionValueHash = hashCode(optionValue);
             var optionLabel = modelElement2label(option);
 
             var selected;
-            if (angular.isArray(viewValue) && viewValue.indexOf(optionValue) !== -1) {
+            if (viewValueHashes.indexOf(optionValueHash) !== -1) {
               selected = true;
             }
             else {
               selected = false;
             }
 
             return {
-              hash: hashCode(option).toString(36),
+              hash: optionValueHash.toString(36),
               label: optionLabel,
               model: option,
               selected: selected