Version 1.7.0

After the time-wrap bug hit Starcoin at block 777855 again and finally stoped the network from producing new blocks the following changes to the protocol were implemented:

1) The ActualSpacing is bound by 2 seconds and TargetTimespan, i.e. 15 minutes
2) The PoW/PoS ratio is set to 1:3 (compare to the original one 1:12) to allow more PoW blocks as anyway for the last half of year the PoS was already broken.
3) The block trust scoring algorithm changed to target 3 PoW blocks among past 12 blocks.