Update to 3.8

Changelog:
For WordPress 3.8 ja
* Update WP Multibyte Patch to 1.9

For WordPress 3.8
Highlights

    Introduces a new, modern admin design
        A fresh, uncluttered design
        Clean typography with Open Sans
        Superior contrast and large, comfortable type
        Responsive interfaces throughout
        Refined, theme management
        Smoother, click-to-add widget management

    New Default Theme - Twenty Fourteen
        Easily create a responsive magazine website with a sleek, modern design.
        Feature your favorite homepage content in either a grid or a slider.
        Use the three widget areas to customize your website, and change your content's layout with a full-width page template and a contributor page to show off your authors.

    For Developers
        External Libraries have been updated.
        Better RTL support

What's New
General

    Replace PNG-based plugins ratings stars with Dashicons for performance gains
    Improved help tab text in various screens
    Clicking "Check Again" on the Updates screen now provides more immediate feedback

Dashboard

    Consolidate several Dashboard widgets to improve readability
    Replace the 'Right Now' widget with the new and improved 'At a Glance' widget

Appearance

    Introduce 8 new admin color schemes
    Improved readability throughout using Open Sans typeface (where supported)
    Responsive Toolbar for smaller-screen devices
    Leverage Dashicons instead of icon sprites for crisper experience on all resolutions
    Big RTL improvements throughout
    Make the dashboard more usable on any size device with responsive all the things
    Improve the login screen experience for Internet Explorer 8 users
    Improve Quick Edit experience for non-English users
    Improve the Menus experience for mobile users

Themes

    New Default Theme -- Twenty Fourteen
    Make it possible to check for any post format assigned to a post with has_post_format()
    Better custom background theme support defaults, can now specify 'default-repeat', 'default-position-x', and 'default-attachment' arguments for background images.
    Tags for width changed to layout: responsive-layout, fluid-layout, and fixed-layout
    New tag: accessibility-ready to denote a theme is aware of accessibility best practices such as color contrast, keyboard navigation, and form/link focus. See WP theme accessibility guidelines.
    Theme screenshots' size have increased from 600x450 to 880x    660.

Widgets

    New click-to-add interface for adding widgets to sidebars
    Improved interface for devices of all resolutions
    Better drag-and-drop experience

Accessibility

    Make list table row actions keyboard accessible
    Improve color contrast throughout the admin

Multisite

    Improved performance when deleting users in Multisite

Under The Hood
General

    Heartbeat performance and API improvements
    A $taxonomy argument was added to each of the adjacent post functions.
    Define $is_nginx in vars.php
    Apply capital_P_dangit() to the wp_title filter
    Make sure ajaxurl is defined in the Customizer
    validate_active_plugins() now checks the manage_network_plugins capability instead of is_super_admin()
    Allow passing false for the meta_box_cb argument in register_taxonomy() to turn off the meta box display entirely
    Make it easier to target video shortcodes by adding a wp-video class to the parent container
    Add CSSMin, SASS, CSSJanus, and jsHint to build tools for core development

Bug Fixes

    Fix bug where top-level categories were only redirecting if they had no children
    Fix bug in wp_get_object_terms() where returned were strings not integers
    Fix a bug where passing a null value to meta_query resulted in wonkiness with the comparison operator
    Fix "'wp_signups' already exists for query" error after updating a Multisite network
    Fix bug in get_bookmarks() caused by missing parentheses
    Fix comment_notification_recipients filter behavior so that it is still respected even on comments left by the post author
    Fix a date comparison error in dashboard_relative_date()
    Fix keyboard accessibility for row actions in list tables.
    Fix no-js and accessibility modes in in the Widgets screen
    Fix a bug where menus could still be assigned to a non-existent theme location
    Silence jQuery Migrate errors in the General settings page

Multisite
Classes

    Introduce WP_Screen::remove_option()
    Introduce WP_Screen::remove_options()
    Introduce WP_Screen::get_options()

Functions

    Introduce wp_dashboard_quick_press()
    Introduce wp_dashboard_site_activity()
    Introduce wp_dashboard_recent_posts()
    Introduce wp_dashboard_recent_comments()
    Introduce wp_dashboard_primary_output()
    Introduce wp_heartbeat_set_suspension()
    Introduce wp_star_rating()
    Introduce get_theme_update_available()
    Introduce wp_prepare_themes_for_js()

Actions & Filters
Actions

    Introduce automatic_updates_complete

Filters

    Introduce automatic_updates_debug_email
    Introduce wp_prepare_themes_for_js

External Libraries

    Add a copyright notice to zxcvbn (password strength meter) script

Deprecated

    screen_icon()
    get_screen_icon()
    wp_dashboard_incoming_links_output()
    wp_dashboard_secondary_output()
    wp_dashboard_incoming_links()
    wp_dashboard_incoming_links_control()
    wp_dashboard_plugins()
    wp_dashboard_primary_control()
    wp_dashboard_recent_comments_control()
    wp_dashboard_secondary()
    wp_dashboard_secondary_control()
    no_update_actions()

Miscellaneous

    Many unused images were removed from core. See the full list


(ryoon)