Objective:
* Allow inserting images from local wiki and commons
Changes:
ve.init.mw.ViewPageTarget.js
* Add media insert button to toolbar
ve.init.mw.Platform.js
* Add getMediaSources method - defaults to local wiki and commons
ve.ui.MWMediaInsertDialog.js
* New dialog for inserting media
* Uses a media select widget and inserts block images
ve.ui.Dialog.css
* Added styling for media select widget in media insert dialog
ve.ui.Widget.css
* Added styles for media select widget and media select item widget
ve.ui.MWMediaInsertButtonTool.js
* New tool for inserting media
ve.ui.MediaSelectItemWidget.js
* New item widget for media select widgets
ve.ui.MediaSelectWidget.js
* New widget for searching for and selecting media items
ve.ui.TextInputWidget.js
* Added isPending method
VisualEditor.i18n.php
* New messages for media insert dialog
VisualEditor.php
* Added links to new files and messages
PhantomJS--
Change-Id: Ia803ff3ef518782ce76802d2dab7559686a1bb0a
