Cleanup vaadin code for managing events and datacollection.

There are still several components that are not working.
Cleanup vaadin code for managing events and datacollection (II).

I got some progress, but there are still things that are not working
properly.
Cleanup vaadin code for managing events and datacollection (III).

Replacing all instances of FieldGroup with BeanFieldGroup.
Use manual binding to avoid potential issues.
Avoid exposing FieldGroup implementation.

Seems to be working better now.
Merge branch 'master' of github.com:OpenNMS/opennms