fixed appendChild method so that it fulfills the specs removing an existing child first
use new DOM API where possible
new command to use appendChild method of new DOM API
some progress in using new DOM API methods only
Merge branch 'feature/ui_rework' of github.com:structr/structr into feature/ui_rework

Conflicts:
	structr-ui/src/main/java/org/structr/web/entity/dom/DOMNode.java