exports: create new aggregator tests + minor corrections in aggregators

src/Bundle/ChillActivityBundle/Export/Aggregator/PersonAggregators/ActivityReasonAggregator.php

@@ -55,10 +55,10 @@ class ActivityReasonAggregator implements AggregatorInterface, ExportElementVali
     {
         // add select element
         if ('reasons' === $data['level']) {
-            $elem = 'reasons.id';
+            $elem = 'actreasons.id';
             $alias = 'activity_reasons_id';
         } elseif ('categories' === $data['level']) {
-            $elem = 'category.id';
+            $elem = 'actreasoncat.id';
             $alias = 'activity_categories_id';
         } else {
             throw new RuntimeException('The data provided are not recognized.');