Fix timespan based sanitation of history items.
Fix timespan based sanitation of history items.

Fixes issue 508.

airodactyl/dactyl,moonshadow/dactyl,Kjwon15/dactyl,madand/pentadactyl-pm,nathyong/dactyl,nathyong/dactyl,airodactyl/dactyl,nathyong/dactyl,nathyong/dactyl,moonshadow/dactyl,airodactyl/dactyl,airodactyl/dactyl,Kjwon15/dactyl,nathyong/dactyl,moonshadow/dactyl,Kjwon15/dactyl,5digits/dactyl,madand/pentadactyl-pm,invl/dactyl,5digits/dactyl,invl/dactyl,Kjwon15/dactyl,invl/dactyl,madand/pentadactyl-pm,moonshadow/dactyl,invl/dactyl,5digits/dactyl,5digits/dactyl,madand/pentadactyl-pm,Kjwon15/dactyl,invl/dactyl,Kjwon15/dactyl,airodactyl/dactyl,madand/pentadactyl-pm,moonshadow/dactyl,invl/dactyl,5digits/dactyl,moonshadow/dactyl,nathyong/dactyl,madand/pentadactyl-pm,airodactyl/dactyl,5digits/dactyl