Update to 4.5.1

Changelog:
4.5.1:
Summary

>From the announcement post, WordPress Version 4.5.1 fixes 12 bugs, chief among them a singular class issue that broke sites based on the Twenty Eleven theme, an incompatibility between certain Chrome versions and the visual editor, and an Imagick bug that could break media uploads.

This maintenance release fixes a total of 12 bugs in Version 4.5 including:

Build/Test Tools

    #36498 Shrinkwrap npm dependencies for 4.5

Bundled Theme

    #36510 Twenty eleven page templates with widgets incorrectly styled

Customize

    #36457 Customizer Device Preview: Use px units for tablet preview size

Database

    #36629 Database connect functions can cause un-catchable warnings

Editor

    #36458 Fix support for Safari + VoiceOver when editing inline links

Emoji

    #36604 Emoji skin tone support test incorrectly passing in Chrome

Feeds

    #36620 Feeds using an rss-http content type are now served as application/octet-stream

Media

    #36501 Fatal error: Undefined class constant 'ALPHACHANNEL_UNDEFINED'
    #36578 wp_ajax_send_attachment_to_editor() bug
    #36621 Don窶冲 cache the results of wp_mkdir_p() in a persistent cache

Rewrite Rules

    #36506 Duplicate directives in web.config after WordPress 4.5 installation on Windows

TinyMCE

    #36545 WordPress TinyMCE toolbar/tabs unresponsive in Chrome Version 50.0.2661.75 beta-m (64-bit)

(ryoon)