Swap items between suggester and actual list

[afoeder]

As soon as an item is selected, it should not be present/selectable in the autosuggester anymore; and vice versa, if an item is removed then, it should be visible in the autosuggester list again.

This must also take care of the initial state when opening a new instance on an already present list; and it should take care of the "availableOptions instead of resource" feature.

[DimitarChristoff]

i will revisit this shortly when I have a need to add tags to a textarea and decouple is sufficiently to be able to do this.