UI Refactor

Changed:

VisualEditor.i18n.php
* Updated Link inspector i18n messages

ve.ui.MetaDialog.js -> ve.ui.PagedDialog
* Moved paging functionality into Paged dialog

ve.ui.EditorPanelLayout -> ve.ui.PagePanelLayout.js
* Renamed from EditorPanelLayout to work nicely with the concept of
  stacks and pages

ve.ui.GroupElement.js
* Added addItem method and change addItems to use it

ve.ui.Dialog.css
* Updated classname as per refactor of meta dialog

ve.ui.StackPanelLayout.js
* Set currentItem property on showItem
* In addItems method, show currentItem with class method
** rather display block on element

ve.ui.Layout.css
* Make editorPanel layout 100% in width.

ve.ui.Widget.css
* Added CategoryWidget and CategoryPopup styles
* Other adjustments

ve.ui.PopupWidget.js
* Added auto-close on loss of focus
* Made friendly with being initialized inside a frame

ve.ui.MWLinkTargetInputWidget.js
* Mixin ve.ui.PendingInputWidget and remove pending methods
* Prevent querying on spaces
* Reintroduce i18n messages for menu sections

ve.ui.MenuWidget.js
* Update cases of $input config property to input

New:

ve.ui.PagedDialog.js
* Refactored base-class for mwMeta dialog (and probably other dialogs
  too)
* Abstracts adding and accessing pages

ve.ui.PendingInputWidget.js
* Moved pushPending and popPending methods into pending class

Change-Id: I29bcd92b7b5641941a4e98e65b2a56424a5263ff
Merge "UI Refactor"