upgrade travis to go1.5.3
upgrade travis to go1.5.3

mnsl/Sia,NebulousLabs/Sia,ChrisSchinnerl/Sia,ChrisSchinnerl/Sia,MrStrong/Sia,NebulousLabs/Sia,MrStrong/Sia,rivine/rivine,mnsl/Sia,mtlynch/Sia,johnathanhowell/Sia,rivine/rivine,mharkus/Sia,ericflo/Sia,mtlynch/Sia,mharkus/Sia,ericflo/Sia