That way we can reduce the number of gettext() messages.

To prevent warnings about missing schema defininitions.

We should make that configurabel in future. But for now vers=3 seems to
be more reliable.

That way we can return file diffs as additional return attribute.

Normaly all nodes should have the same version, so /api2/json/version is
good enough for most situations. But you can also query the version on
each node using /api2/json/nodes/{node}/version