add build constant information to 'siad version'
add build constant information to 'siad version'

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