update the host default price and collateral values
update the host default price and collateral values

The price of siacoin has gone up substantially since the last release,
meaning that the defaults are now very high. This adjusts the defaults
down to more reasonable levels.

The defaults have also been adjusted a bit to help target a healthy,
competitive network.

The collateral in particular is lower than what was previously
recommended (even adjusted for the siacoin price change) because renters
had been making more contracts than using them, zapping many hosts of
all their collateral.

The lower collateral price should help the hosts get farther while the
network bootstraps. We may need to reconsider some things if the renters
continue to allocate more collateral than they use, but lazy contract
formation should help substantially.

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