docs on navigationService

working ngDocs setup, started adding docs to navigation and dialog
service
Merge branch '7.0.0' of https://github.com/umbraco/Umbraco-CMS into 7.0.0

Conflicts:

src/Umbraco.Web.UI.Client/src/common/directives/umbtreeitem.directive.js
	src/Umbraco.Web.UI.Client/src/common/services/navigation.service.js