core/vm: check empty in extcodehash

Change the type of the metered connection's id field from string to enode.ID.

* swarm, cmd/swarm: address ineffectual assignments

* swarm/network: remove unused vars from testHandshake

* swarm/storage/feed: revert cursor changes

* RequestFromPeers does not use peers marked as lightnode

* fix warning about variable name

* write tests for RequestFromPeers

* lightnodes should be omitted from the addressbook

* resolve pr comments regarding logging, formatting and comments

* resolve pr comments regarding comments and added a missing newline

* add assertions to check peers in live connections

* core: speed up GenerateChain

Use a mock implementation of ChainReader instead of creating
and destroying a BlockChain object for each generated block.

* eth/downloader: speed up tests by generating chain only once

This change reworks the downloader tests so they share a common test
blockchain instead of generating a chain in every test. The tests are
roughly twice as fast now.

* signer: remove ineffectual assignments

* signer: remove ineffectual assignments

* downloader: measure successfull deliveries, not failed

* downloader: fix typos

* swarm: Better syncing and retrieval option definition

* swarm/network/stream: better comments

* swarm/network/stream: addressed PR comments

* swarm: modify context key

* gofmt sctx.go

* swarm: clean up unused private types and functions

Those that were identified by code inspection tool.

* swarm/storage: move/add Proximity GoDoc from deleted private function

The mentioned proximity() private function was deleted in:
1ca8fc1e6fa0ab4ab1aaca06d6fb32e173cd5f2f

* p2p/protocols: introduced protocol accounting

* p2p/protocols: added TestExchange simulation

* p2p/protocols: add accounting simulation

* p2p/protocols: remove unnecessary tests

* p2p/protocols: comments for accounting simulation

* p2p/protocols: addressed PR comments

* p2p/protocols: finalized accounting implementation

* p2p/protocols: removed unused code

* p2p/protocols: addressed @nonsense PR comments

* cmd/clef: replace password arg with prompt (#17829)

Entering passwords on the command line is not secure as it is easy to recover from bash_history or the process table.
1. The clef command addpw was renamed to setpw to better describe the functionality
2. The <password> argument was removed and replaced with an interactive prompt

* cmd/clef: remove undeclared variable

   __
 <(o )___
  ( ._> /
   `---' 

This fixes the import cycle build error in core/vm tests.
There is no need to refer to core/vm for a type definition.

This adds the global accumulated refund counter to the standard
json output as a numeric json value. Previously this was not very
interesting since it was not used much, but with the new sstore
gas changes the value is a lot more interesting from a consensus
investigation perspective.

* swarm/network/stream: disambiguate chunk delivery messages (retrieval vs syncing)

* swarm/network/stream: addressed PR comments

* swarm/network/stream: stream protocol version change due to new message types in this PR