add a spec for cron + first_in
add a spec for cron + first_in

in reply to gh-93

"last_time" != "first_time"

0612800232/rufus-scheduler,moritoru81/rufus-scheduler,safesoftware/rufus-scheduler,moss-zc/rufus-scheduler,railsfactory-kumaresan/rufus-scheduler,kssminus/rufus-scheduler,shutl/rufus-scheduler,AndBicScadMedia/rufus-scheduler,jmettraux/rufus-scheduler