Fixed missing creation time of motion version.
Show now string if identifier is not set set (in widgets and motion detail).
Merge pull request #869 from emanuelschuetze/1.4.2-fixes

Fixes for motion version and identifier
Merge remote-tracking branch 'openslides/stable/1.4.x'
Fix delete of assignments with related agenda items.
Merge pull request #873 from normanjaeckel/FixDeleteAssignment

Fix delete of assignments with related agenda items.
Merge remote-tracking branch 'openslides/stable/1.4.x'

Conflicts:
	openslides/assignment/models.py