functions.php

<?php

/**
 * Return a short path for the assets folder.
 * */
function assetsDirectory()
{
    $path = esc_url(get_template_directory_uri()) . '/assets/';

    return $path;
}

/**
 * Remove WordPress Admin bar.
 */
add_filter('show_admin_bar', '__return_false');

/**
 * Remove WP Emoji... Not sure why it comes by default.
 */
function disable_wp_emojicons()
{
    // all actions related to emojis
    remove_action('admin_print_styles', 'print_emoji_styles');
    remove_action('wp_head', 'print_emoji_detection_script', 7);
    remove_action('admin_print_scripts', 'print_emoji_detection_script');
    remove_action('wp_print_styles', 'print_emoji_styles');
    remove_filter('wp_mail', 'wp_staticize_emoji_for_email');
    remove_filter('the_content_feed', 'wp_staticize_emoji');
    remove_filter('comment_text_rss', 'wp_staticize_emoji');

    // filter to remove TinyMCE emojis
    add_filter('tiny_mce_plugins', 'disable_emojicons_tinymce');
}

add_action('init', 'disable_wp_emojicons');

function disable_emojicons_tinymce($plugins)
{
    if (is_array($plugins)) {
        return array_diff($plugins, array('wpemoji'));
    } else {
        return array();
    }
}

/**
 * More head cleanup.
 */
remove_action('wp_head', 'wlwmanifest_link');
remove_action('wp_head', 'rsd_link');
remove_action('wp_head', 'wp_generator');

/**
 * Use Post Category to load template
 */
add_filter('single_template', create_function(
        '$the_template',
        'foreach( (array) get_the_category() as $cat ) {
		if ( file_exists(TEMPLATEPATH . "/templates/single-{$cat->slug}.php") )
		return TEMPLATEPATH . "/templates/single-{$cat->slug}.php"; }
	return $the_template;')
);

/**
 * Customize login logo
 */

function my_login_logo() { ?>
    <style type="text/css">
        .login h1 a {
            background-image: url(<?php echo get_stylesheet_directory_uri(); ?>/assets/img/admin.png);
            padding-bottom: 30px;
        }
    </style>
<?php }
add_action( 'login_enqueue_scripts', 'my_login_logo' );