Initial commit for Dialog component

Includes initial test setup
Add createElements method to Dialog component
Bump dough-ruby version and correct renamed partials
First pass of the Dialog component
Add test for content setting and fix broken hide test

General tidy up: remove some of the commented code, redundant tests.
The ESC keyup event is being picked up by the dialog so have left a
note in there to look further into this.
Prohibit dialog from further opening/closing if open/closed
Update Dialog test language
Allow HTML5 Dialog show() and showModal() to be called
Search Dialog target element directly, not via
Delegate the close button click events via $dialog
Remove cancel()  method

cancel functionality can now be called by passing true to close();
Rename method setContent to appendTargetToDialog
Explicitly pass false to close() when close button is clicked
Add correct property type checking for Dialog
Add classes to created dialog elements
Chain some of the jQuery method calls
Add tests for showModal and cancelled modal
Fix indentation errors and remove some examples

Removed `<dialog>` HTML (not needed as it is generated programatically)
and LinkInserter (this is coming on a separate feature)
Merge pull request #84 from moneyadviceservice/dialog-component

Dialog component