Initial requirements for Release-feature
Make backlogs issue history-function usable for release history.

Possibly candidate of refactoring to move sprint specific logic away from history().
Initial rework of release graph
Update new release graph to use unified journal
Updated CSV export for new release graph data
Merge branch 'master' into bohansen_release_chart

Conflicts:
	app/models/rb_release.rb
	app/views/rb_release_burndown_charts/_burndown.html.erb
	config/locales/fr.yml
Merge branch 'master' into bohansen_release_chart
Merge branch 'master' into bohansen_release_chart
Merge remote branch 'backlogs/master' into bohansen_release_chart
Corrected sprint selection for release
start releases-issue relations: issue edit hooks
issue filter and stuff

rename migration number
releases tests

revert release link id
prepare release backlog api
adapt tests
nicer release backlog on release page
render release backlogs on master bl page, remove stories from product backlog if they are in a release

template for release header in mbp

use headertext selector for release template
fix story-by-release calculation
frontend: post release_id on drag-save

post release_id only if we go into a release (set) or into backlog (remove)
sort releases on mbp