Memory Exhaustion issue - added limit to query

calling simple_history_get_items_array can cause a memory exhaustion error. 

Using the following code in a custom plugin/theme to show the history, we get an exhaustion error.
```PHP
$args = array("filter_user" => $current_user_id);
$logs = simple_history_get_items_array($args);
```
Added the SQL update to use a limit based on page and pager amount to prevent this.