Add function for converting unix time in seconds

Change-Id: I96e3b81493058a26787c476a0c6d252e1f6b39a0
Reviewed-on: http://fulliautomatix.ics.uci.edu:8443/224
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Taewoo Kim <wangsaeu@gmail.com>
6 files changed