This adapts the signature of the following methods to accept a vararg
parameter instead of a plain array:

FilteredList:
- setElements(Object[]) -> setElements(Object...)
- setSelection(int[]) -> setSelection(int...)
- setSelection(Object[]) -> setSelection(Object...)

AbstractElementListSelectionDialog:
- setListElements(Object[]) -> setListElements(Object...)
- setSelection(Object[]) -> setSelection(Object...)

This stops callers from having to explicitly create an array when e.g.
selecting a single element. For example `filteredList.setSelection(new
int[]{0})` can be simplified to `filteredList.setSelection(0)`.