Merge branch 'hotfix/restore_db_correct_max_ids'
Merge branch 'release/1.6.0'
Merge branch 'release/1.6.1'
Update version number: 1.6.1
Update README.md
Update README.md
Merge branch 'release/1.6.2'

Conflicts:
	Puli/README
Check key error when deleting rendernode

Fix an error when a request is sent to delete a rendernode.
Still need to fix the fact that the node deletion is called twice (see rendernode change listener)
Merge branch 'hotfix/delete_rendernode_error' into develop