This is better because protocols might not actually read the payload for
some errors (msg too big, etc.) which can be a pain to test with the old
behaviour.

This helps a lot with debugging.

Message encoding functions have been renamed to catch any uses.
The switch to the new encoder can cause subtle incompatibilities.
If there are any users outside of our tree, they will at least be
alerted that there was a change.

NewMsg no longer exists. The replacements for EncodeMsg are called
Send and SendItems.

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