Issue 1: Replace EditorCookie.getOpenedPanes with NbDocument.findRecentEditorPane 

see https://github.com/markiewb/nb-sort-line-tools/issues/1
Issue 2: Remove warnings while building

* remove warnings about atomic lock
* see https://github.com/markiewb/nb-sort-line-tools/issues/2
Issue 2: Remove warnings while building

* add explicite dependency to lookup api
Issue 2: Remove warnings while building

* use typed comparator
Issue 3: Convert layer-based action registration to annotation-based approach
[release] create new package