Initial commit of LinkInsert with tests and fixture

Tests are very loose at the moment.
Adds some base CSS formatting tabs components...

.l-tab-panels and .tab-selector components. Looking to move Modernizr
into the actual Dough package.
Set active/inactive states on Dialog target content

Fixes issue with vertical/horizontal positioning of Dialog when opened
Toggle active/inactive class on the dialog element
Add insert link dialog when create and edit pages
Remove unecessary item content on the page dialog
Add Modernizr to the pages

* This commit fix "Uncaught ReferenceError: Modernizr is not defined"
Adds active/inactive state classes to Dialog target
Adds a dialog active state to body tag...

…so that we can allow the dialog to control the scrolling when it is
open
Add an additional dialog__content-wrapper elem

Allows for more flexibility when trying to vertically/horizontally
position the content
Refactor the Dialog's inserted HTML

contentWrapper is no longer, replaced with containerInner
Append the Dialog target to contentInner

So that we can absolutely position the close button within the main
Dialog content area.
Vertically/horizontally align the Dialog to screen

Also formats the backdrop
Blur the content behind when the dialog is open
Hides the Add Link dialog
Activity log - hide tabs by default
Separate each page link tab to your own partial
Make save page a protected method like comfy code
Add is inactive to the page files tab content
Use Sinon's sandbox