Now, a timeout can be specified to block until new events reach a single channel
or the specific timeout expires.

If get_utc_ts_from_fmc_dio_device returns EAGAIN, we have to check later because
there are not more timestamps (Other errors cause an exit).

It helps to identify the number of times that run() function is called for the
stats-engine. This is useful just to compare with the number of timestamps received.

Register the two (leapSecond info and timestamp) at exactly the
same time. Still not perfect but better than before.

FMC DIO device supports leap seconds fields for the timestamps. A new
usr-timestamp type has been created to deal with differences between timespec
and new FMC DIO timestamps.
- New fields for leap-seconds in fmc-dio-device driver
- Create usr-timestamp type for irq-demo
- Conversion mechanism from fmc-dio timestamp to usr-timestamp