WooCommerce - change add to cart button text on product archives

## functions.php
add_filter( 'add_to_cart_text', 'woo_custom_cart_button_text' );                        // < 2.1
add_filter( 'woocommerce_product_add_to_cart_text', 'woo_custom_cart_button_text' );    // 2.1 +

function woo_custom_cart_button_text() {

        return __( 'My Button Text', 'woocommerce' );

}
	add_filter( 'add_to_cart_text', 'woo_custom_cart_button_text' ); // < 2.1
	add_filter( 'woocommerce_product_add_to_cart_text', 'woo_custom_cart_button_text' ); // 2.1 +

	function woo_custom_cart_button_text() {

	return __( 'My Button Text', 'woocommerce' );

	}