defuse and fix translation-manager
translations
Change filter_release to not expand history.
The algorithm might be searching outside boundary of a story's history and doesn't need the expanded history.
Expanding was very expensive for releases over a large timespan.
test for #855
do not change project_id on update of sprint/release from master backlog page, fixes #855
Merge pull request #850 from backlogs/translations

Translations fixes #843
Merge pull request #857 from backlogs/bug/855-versionchangesproject

Bug/855 versionchangesproject
Translations updated
some more german translations
re #829 take into account that higher_items may be in another sprint
board updater support for release backlogs
clarify higher_item method in activerecord_mixin
test for higher_item

reformat debug output of higher_item dump

elaborate list_with_gaps feature
use scope for higher_item: higher is what is seen visually on a backlog (sprint/productbl etc.), not next position
note problematic code regarding higher_item
tests: default to sprints project if not given in background table
when moving stories, use :next like the frontend does
remove up/down direction from story move tests
re #842 enable passing list_with_gaps tests
travis: drop 2.0, add list_with_gaps