Non blocking dependencies

New features

• Added possibility to load dependency in non-blocking mode
• Added BootstrapListener mechanism to Flow so that the contents of the generated head tag can be modified

Fixes

• Child components inside ShadowRoot should find the UI through Component.getUI()

Breaking changes

• RouterLink attribute has been changed from routerlink to router-link

Demos

• Example web site demo updated with an added BootstrapListener

Tutorials

• Added Non-blocking Importing
• Added Modifying bootstrap page
• Updated RouterLink tutorials (routerlink to router-link)

All changes

https://github.com/vaadin/flow/milestone/30?closed=1