[core] fix data table export bug

Author: waiterZen

frontend/express/public/javascripts/countly/countly.helpers.js

@@ -305,6 +305,22 @@
                 tableData = app.dataExports[tableCols[0].sExport]();
             }
             else{
+                // TableTools deprecated by offical, 
+                // fix bug with workaround for export table
+                TableTools.fnGetInstance = function ( node ) {
+                        if ( typeof node != 'object' ) {
+                            node = document.getElementById(node);
+                        }
+                        var iLen=TableTools._aInstances.length;
+                        if(iLen > 0){
+                            for ( var i = iLen - 1 ; i >= 0 ; i-- ) {
+                                if ( TableTools._aInstances[i].s.master && TableTools._aInstances[i].dom.table == node )  {
+                                    return TableTools._aInstances[i];
+                                }
+                            }
+                        } 
+                        return null;
+                }; 
                 tableData = TableTools.fnGetInstance(dtable[0]).fnGetTableData({"sAction":"data","sTag":"default","sLinerTag":"default","sButtonClass":"DTTT_button_xls","sButtonText":"Save for Excel","sTitle":"","sToolTip":"","sCharSet":"utf16le","bBomInc":true,"sFileName":"*.csv","sFieldBoundary":"","sFieldSeperator":"\t","sNewLine":"auto","mColumns":"all","bHeader":true,"bFooter":true,"bOpenRows":false,"bSelectedOnly":false,"fnMouseover":null,"fnMouseout":null,"fnSelect":null,"fnComplete":null,"fnInit":null,"fnCellRender":null,"sExtends":"xls"});
                 tableData = tableData.split(/\r\n|\r|\n/g);
                 tableData.shift();