- inverted check in SwDoc::RemoveInvisibleContent
- various too short end positions in DeleteAndDestroy calls in
  SwDoc::~SwDoc and SwDoc::ClearDoc
- std::copy to begin() of empty vector in SwReader::Read replaced
  with std::back_inserter; the vector is used as a set here so the
  end position should work just as well

Change-Id: Ib2ddd788fade4ee1a8beb702d5321c503985fba4