timer: convert sigaction to sigwaitinfo
timer: convert sigaction to sigwaitinfo

Currently, this example attach a signal handler to catch the
notifications using sigaction(). But signal handler is very slow.
So, a much more efficient thing to do is to create a separate
pthread that waits on sigwaitinfo() for timer events. in additional,
much less overhead in that case.

Change-Id: I82aaf9a532b86d40ff641b17ef28ebc0c6987e93
Signed-off-by: Jihun Ahn <31fe625dd60d1475d1b18ea57157c450e67c870a@samsung.com>

JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT