1.0.0-beta.43 Dark mode!

• Introduced dark color scheme a.k.a. dark mode. Various fixes and improvements in views markup and styles
• Improved loading progress overlay repaints to avoid freezing when document became inactive
• Added Widget#pathToQuery(path) method
• Added toggle and toggle-group views
• Changed a bit default page in model free mode
• Fixed children option ignorance in itemConfig when limitLines is used for tree view
• Fixed href option to work for button view
• Fixed path generation in signature details
• Fixed context for Widget#nav.menu item rendering