Elapsed time in milliseconds, with both whole seconds and the rest

May cause an Int overflow, use only with a low number of seconds.

Property definitions

realtime $ Timespec :: millisec
	# Elapsed time in milliseconds, with both whole seconds and the rest
	#
	# May cause an `Int` overflow, use only with a low number of seconds.
	fun millisec: Int `{
		return self->tv_sec*1000 + self->tv_nsec/1000000;
	`}
lib/realtime/realtime.nit:132,2--137,3