- switched system jump/kill-data update cronjob from XML API to ESI

- use internal DEBUG level for MySQL ERRORMODE
- increased MySQL version 5.6 => 5.7
- fixed bug in System auto search form element (select2)
- code cleanup

js/app/ui/form_element.js

@@ -148,7 +148,10 @@ define([
             }).on('select2:open', function(){
                 // clear selected system (e.g. default system)
                 // => improves usability (not necessary). There is a small "x" whe it could be cleared manually
-                if($(this).val() !== null){
+                if(
+                    options.maxSelectionLength === 1 &&
+                    $(this).val() !== null
+                ){
                     $(this).val('').trigger('change');
                 }
             })