Log Message:
Update to version 4.8.1.

WordPress 4.8.1 contains 29 maintenance fixes and enhancements to the 4.8 \ 
release series, chief among them are fixes to the rich Text widget and the \ 
introduction of the Custom HTML widget.

Administration
* #40982 - Permalink Settings: custom structure field keyboard trap

Build/Test Tools
* #41327 - Bump Akismet External - 4.9 Edition

Comments
* #40975 - 'Empty Spam' and 'Empty Trash' comment buttons not displayed on mobile

Customize
* #40978 - Customizer Panel Footer border missing
* #40981 - Customizer: Menus: it is far too easy to mistakenly delete a menu \ 
because the "Delete Menu" link and the "Add Items" button \ 
are too close together
* #41158 - Increase tinymce panel z-index
* #41410 - Set `'filter' => 'content'` on starter content "business \ 
info" widget

Embeds
* #41019 - oEmbed: Update VideoPress oEmbed URL
* #41048 - `WP_oEmbed_Controller::get_proxy_item()` should remove `_wpnonce` \ 
from cached `$args`
* #41299 - oEmbed proxy fails to forward maxwidth and maxheight params

General
* #41056 - WP-API JS Client: Settings is incorrectly registered as a collection

Media
* #41231 - media-views.js: Cannot read .length of undefined \ 
(this.controller.$uploaderToggler.length)

REST API
* #38964 - Add filter to allow modifying response *after* embedded data is added
* #40886 - REST API: PUT requests fail on Nginx servers when fancy permalinks \ 
aren't enabled

Taxonomy
* #41010 - wp_get_object_terms() returns duplicate terms if more than one \ 
taxonomy is given in args

TinyMCE
* #41408 - TinyMCE: Images with link and caption look "broken" when \ 
selected

Widgets
* #40907 - Introduce widget dedicated for HTML code
* #40935 - Facebook Video Works On Preview But Not On Theme
* #40951 - New Text Widget - Switching Between Visual/Text Editor Strips Out Code
* #40960 - Widgets: The Text widget should respect the “Disable the visual \ 
editor when writing” setting
* #40972 - TinyMCE editor in Text widget does not have RTL contents
* #40974 - Updated text widget do not save text (when using paste)
* #40977 - Widgets: Query param for `loop` added for non-hosted external videos
* #40986 - Widgets: text widget and media widgets cannot be edited in \ 
accessibility mode
* #41021 - Text widget does not show Title field or TinyMCE editor
* #41361 - Text widget can raise JS error if customize-base is enqueued on \ 
widgets admin screen
* #41386 - Text Widget - Wording - Legacy Mode 4.8.1 beta
* #41392 - Theme styles for Text widget do not apply to Custom HTML widget
* #41394 - Text widget: Rename legacy mode to visual mode and improve \ 
back-compat for widget_text filters