Accumulation of events

[simongregorebner]

When channels are fireing very frequently and "heavy" computation is done in the property listener, events get accumulated and listeners are fires although the channel is not sending any changes any more.
In some cases this behaviour is desired but in some are not (e.g. displaying stuff at the GUI).

Therefor we need to decouple things via a queue of size 1 (option to choose)