NEWS: prepare for 6.6.4
Event/DelayedNotify: cancel the timer
Dialogs/FileManager: cancel the timer
Volkslogger IGC download. Increase timeout.

Increase the timeout to wait for the VL to calculate security for 5min to
10min.
See ticket #2910
Merge remote-tracking branch '_max/v6.6.x' into v6.6.x

Conflicts:
	NEWS.txt