Bug/842 boardupdater4 - fix auto-refresh by scoping list_with_gaps higher/lower_item

platform:  # supported: 2.0.4, 2.1.6, 2.2.3
backlogs:  # supported: 0.9.36
ruby:  # supported: 1.9.3, 1.8.7

fixes #842 
fixes #829 
fixes #668 

Also some refactoring for RbStory find_options,
some test fixes which tested other behavior than the user interface,
removed some duplicated tests from sharing