Bump Vaadin version to 7.1.6
Add FieldQuery.removeValueChangeListener
Move hierarchy traversal methods from Query to AbstractQuery
Add missing superclass constructor to Query
Use the form "for(X x: this)" consistently
Add many new FieldQuery tests
Add demo config to ivy.xml, remove unneeded EasyMock dependency
Considerably improve AbstractQuery javadocs
Add addAfter(), addBefore(), first(), last() methods to AbstractQuery

Also refactor internal handling of indexed layouts