New Layouts: VerticalLayout and HorizontalLayout

New Features

• Added VerticalLayout
• Added HorizontalLayout

Demos

• New demo for VerticalLayout
• New demo for HorizontalLayout
• Demo source code is now displayed alongside the demo
• The demo menu has been restructured

Breaking Changes

• Using @Id annotation for elements inside nested templates is now explicitly prohibited

Fixes and Improvements

• Dom events with null data no longer throw an exception
• Using @Convert on template model getters is now supported
• Bootstrapping performance has been improved
• The exception message for when multiple components use the same @Tag and are not in the same class hierarchy has been improved
• The exception message for when a template model receives an unexpected value from the client has been improved

All Changes

• https://github.com/vaadin/flow/milestone/45?closed=1