The encoder was missing a special case for one element strings whose
element is below 0x7f. Such strings must be encoded as a single byte
without a string header.

Merge branch 'frontier/cli-private-network' of https://github.com/ethersphere/go-ethereum into ethersphere-frontier/cli-private-network

Dockerfile: use fast™ build steps

cmd/ethereum: add makedag command for testing

This also changes the chain export format so there is no
enclosing list around the blocks, which enables streaming export.

Über-convenience.

- protocolversion, networkid global int flags to cli and mist
- fix bug with protocolversion check using wrong db
- log protocolversion & networkid in backend

All other pointer types can handle nil just fine.

http://www.jsonrpc.org/specification#batch

DRY up the use of toHex in the project and move it to common

Frontier console node admin interface