Apply patch from Chuso Perez

"MainWindow tries to connect TrayIcon slots to some signals sent by
TimetrackerWidget. But these signals are not being emitted by
TimetrackerWidget, they are being emitted by TaskView.
This code patches TimetrackerWidget to receive those TaskView signals
and propagate them so MainWindow can receive them to connect them to
TrayIcon."

REVIEW: 107482