Changes to logic.

New logic of adding post is. Posts will be added to a shared collection named "Attacher Shared Resources". This collection will be created into a user root collection if missing. Also introduced changes to API calls to comply to latest changes (using JS SSSClientSide library as a reference).
Added shared collections to select list.

Had to change some method calls as getting collection tags and searching for resources from tags is sensitive to the provided user URI (using the collection author uri to get results).
More changes to the API calls.
Clean up.