Alpha 2: Grid and more Router features

New Features

• Added more Router features:
  • @OptionalParameter #2293
  • Update RouterLink to work with new Routing #2440
  • Automatically register a Vaadin servlet for the new router #2439
• Grid
  • Single selection #2180
  • Implement data lazy loading support for Grid #2423
• VaadinIcons #2341

Bug fixes

• Client-side assertion exception #2305
• Fixed Text-field validation errors #2519

Breaking Changes

• Replace the custom JSoup implementation for the standard one. #1519
• Removed selected-item-changed and change events on VaadinComboBox. Now the setValue and addValueChangeListener is used for all cases #2092
• ComboBox now uses ItemLabelGenerator to define the labels for items. The setItemXXXPath methods were removed. #2177
• Old router was deprecated and is up for removal in the near future #2494

All Changes

https://github.com/vaadin/flow/milestone/51?closed=1