Rather than hacking the core, you should put that code into your theme’s functions.php. That’s what apply_filters and add_filter is for!!!!!!!!!!
Add this to your theme’s functions.php:
add_filter( 'get_topic_title', 'strip_the_title_slashes', 20, 2);
function strip_the_title_slashes( $title, $id ) {
return stripslashes( $title );
}
add_filter( 'get_post_text', 'strip_the_text_slashes', 20, 2);
function strip_the_text_slashes( $text, $id ) {
return stripslashes( $text );
}