Sync with Geth source code

Our bane-main is out-of-date with https://github.com/ethereum/go-ethereum, we need to review changes happened since the last merge and sync our codebase.

We also need to think about sync strategy: how often, how to sync with Bane releases, etc.

A side note: #113 may already be fixed in the original Geth Clique code.