play.py: send ItemsChanged iso PropertiesChanged
play.py: send ItemsChanged iso PropertiesChanged

By default, send all changes that happen at the
same time as a single ItemsChanged signal on the
root path.

This replaces the previous implementation with
a PropertiesChanged message on root.

The old behaviour where individual PropertiesChanged
messages are sent is still possible by passing the
--nozip commandline option to play.py.

https://github.com/victronenergy/venus/issues/789

victronenergy/dbus-recorder,victronenergy/dbus-recorder