test some more complex sharing updater cases
move board updater test for stories from team_member to updater.feature, take sharing into account
negative tests on sharing, failing currently
Revert "board-updater: take sharing into account"

This reverts commit 1fa9743ac313f748cf6a610abc7edad604c753fb.
updater checks for correct scope

use scopes for find_options in updater
scope taskboard updater to sprint
shared last_update on master bl page
rename list_with_gaps_scope
use Array union to join scoped updated stories
make private rb_story methods private
list_with_gaps method rename: lower/higher_item are scoped, the unscoped ones are private
remove duplicated tests
include updater.feature in travis