get rid of FILTER_SANITIZE_STRING everywhere

MysqliDb.php

@@ -395,7 +395,7 @@ class MysqliDb
      */
     public function query($query, $numRows = null)
     {
-        $this->_query = filter_var($query, FILTER_SANITIZE_STRING);
+        $this->_query = $query;
         $stmt = $this->_buildQuery($numRows);
         $stmt->execute();
         $this->_stmtError = $stmt->error;
@@ -693,7 +693,7 @@ class MysqliDb
             die ('Wrong JOIN type: '.$joinType);
 
         if (!is_object ($joinTable))
-            $joinTable = self::$prefix . filter_var($joinTable, FILTER_SANITIZE_STRING);
+            $joinTable = self::$prefix . $joinTable;
 
         $this->_join[] = Array ($joinType,  $joinTable, $joinCondition);