Initial Polymer template support

New features

• WebComponents annotation to specify polyfill version
• Added PolymerTemplate class
• Polymer template client -> server event handler
• Old Angular template class Template renamed to AngularTemplate

Fixes

• Updated GWT version to 2.8.0
• Picked fixes from Framework v7 and v8

Performance tests

• Expense manager application scalability test
• Expense manager application memory test

Demos

• Polymer minesweeper (Only works in Chrome)
• Polymer addressbook

Tutorials

• New tutorial on rerouting functionality

All changes

https://github.com/vaadin/hummingbird/milestone/21?closed=1