Miscellaneous pre-beta changes

New features in alpha 10

• A list of breaking and incompatible changes in FW 8
• Change defaults of VerticalLayout and HorizontalLayout
  • HorizontalLayout now has spacing on by default
  • VerticalLayout now has margins and spacing on by default
  • Compatibility versions of the layouts exist with the old defaults
• Most single-method interfaces are now functional interfaces
• Listener interfaces have been reorganized somewhat
• Upload component is in immediate mode by default
• Client side module vaadin-widgets has been removed
• ThreadLocals are no longer inherited by other threads
• Grid::addColumn() without renderer now accepts any type
  • the value is converted to a string
• Many data binding API related packages, classes and methods have been moved/renamed
  • com.vaadin.server.data -> com.vaadin.data.provider
  • com.vaadin.data.util.converter -> com.vaadin.data.converter
  • etc.
• Added ValueProvider interface and some other common interfaces
• Redesigned Grid use of column identifiers
• Extracted interfaces from Grid
• Added SortListener for Grid
• Vaadin Spring version is listed in Vaadin BOM
• etc.

Existing features added from version 7

• Declarative layout support for Grid
• Sorting of Grid from the server side
• All changes introduced by 7.7.5 are migrated into master for FW 8 and compatibility components when applicable

In addition to these, several small changes and fixes are included in 8.0.0.alpha10.