New plugin automation examples

[lalala]

Redo never worked correctly with AudioProcessorValueTreeState, it’s a known bug :

Redo issue with PluginStateValueTree. SetPropertyAction & excludeListener

AudioProcessorValueTreeState::Parameter::copyValueToValueTree() calls setPropertyExcludingListener(), giving this as listener to exclude. That creates a ValueTree SetPropertyAction() with that Parameter given as ‘excludeListener’. In consequence, when redo is called, SetPropertyAction::perform() will be called, but the parameter won’t be notified by the change. Note that it “sometimes” work in practice, because you often modify your parameter twice in a row (through a slider drag for instance…