If the user closes the UI before the broadcast has completed, we would
stop broadcasting. Which is unfortunate and not what users expect.
As such we simply hold on to the object for a while (10 min) before we
delete it when it is quite likely already sent.
The Sweep feature needs the 'previous' transactions to build the new
transaction.
This shows a progress-report per-transaction as they are downloaded.
Additionally this splits the incoming electron-X reply into lines before
processing.
This separates it into two objects in order to make thead-safety easy
using Qt's signal/slot mechanism.
Additionally this removes magic timeout numbers and simply starts a
timer to check for changes and emit a signal if the status actually
needs updating.
Testing also shows that QML calls the getter a LOT, so I also moved the
broadcastStatus to be buffered and just return that on the call.
This incidentally also simplifies the code, double win.
tomFlowee