add support for relaying txns to old clients
add support for relaying txns to old clients

kustomzone/Sia,ericflo/Sia,Mingling94/Sia,NebulousLabs/Sia,mtlynch/Sia,rivine/rivine,mnsl/Sia,johnathanhowell/Sia,MrStrong/Sia,NebulousLabs/Sia,MrStrong/Sia,rivine/rivine,ericflo/Sia,mharkus/Sia,ChrisSchinnerl/Sia,ChrisSchinnerl/Sia,mnsl/Sia,mharkus/Sia,mtlynch/Sia