Addon test helpers

Provides e.g. searchable list and embedded server for UI's on the test packages, essential serious add-on projects. Also contains some helpers for TestBench/Selenium.

See archetypes configuring this add-on automatically for your add-on projects:

• Archetype for plain servers side and/or JS components
• Archetype for traditional GWT components

Also contains a component to dynamically adjust properties of components within given "component tree", but that is broken (pending some V6->V7 upgrade fixes).