if start dates are equal, sort by end date.
changelog.
Adds migration that fixes old journals.

Parent ids in planning element journals remained the same during the
earlier journal migrations and need to be fixed. This migration works
for postgres only.
Merge remote-tracking branch 'opf/feature/rails3' into fix/migration-of-legacy-planning-element-journals

Conflicts:
	doc/CHANGELOG.md
Fixes planning element migration
Adds changelog entry
Adds missing method.
Merge remote-tracking branch 'opf/feature/rails3' into fix/migration-of-legacy-planning-element-journals

Conflicts:
	doc/CHANGELOG.md
Merge pull request #677 from opf/fix/missing_responsible_migration

[FIX] Missing responsible migration
Merge remote-tracking branch 'opf/feature/rails3' into feature/timelines_sort_end

Conflicts:
	doc/CHANGELOG.md
Merge pull request #671 from opf/feature/timelines_sort_end

timelines include end date into sorting
Merge pull request #673 from opf/fix/migration-of-legacy-planning-element-journals

Adds migration that fixes old journals.