* cmd/utils: Add check on hard limit, skip test if below target

* cmd/utils: Cross platform compatible fd limit test

* cmd/utils: Remove syscall.Rlimit in test

* cmd/utils: comment fd utility method

* swarm/api: url scheme bzz-hash to get hashes of swarm content (#15238)

Update URI to support bzz-hash scheme and handle such HTTP requests by
responding with hash of the content as a text/plain response.

* swarm/api: return hash of the content for bzz-hash:// requests

* swarm/api: revert "return hash of the content for bzz-hash:// requests"

Return hashes of the content that would be returned by bzz-raw
request.

* swarm/api/http: handle error in TestBzzGetPath

* swarm/api: remove extra blank line in comment

* cmd, core, eth/tracers: support fancier js tracing

* eth, internal/web3ext: rework trace API, concurrency, chain tracing

* eth/tracers: add three more JavaScript tracers

* eth/tracers, vendor: swap ottovm to duktape for tracing

* core, eth, internal: finalize call tracer and needed extras

* eth, tests: prestate tracer, call test suite, rewinding

* vendor: fix windows builds for tracer js engine

* vendor: temporary duktape fix

* eth/tracers: fix up 4byte and evmdis tracer

* vendor: pull in latest duktape with my upstream fixes

* eth: fix some review comments

* eth: rename rewind to reexec to make it more obvious

* core/vm: terminate tracing using defers

params: add Rinkeby bootnode from Akasha

ethkey is a new tool that serves as a command line interface to
the basic key management functionalities of geth. It currently
supports:
 
 - generating keyfiles
 - inspecting keyfiles (print public and private key)
 - signing messages
 - verifying signed messages

This change inlines the logic of bytesAreProper at its sole
callsite, ABI.Unpack, and applies the multiple-of-32 test only in
the case of unpacking methods. Event data is not required to be a
multiple of 32 bytes long.

Changed the communication protocol for ordinary message,
according to EIP 627. Messages will be send in bundles, i.e.
array of messages will be sent instead of single message.

Fixes #15617

* crypto: ensure that VerifySignature rejects malleable signatures

It already rejected them when using libsecp256k1, make sure the nocgo
version does the same thing.

* crypto: simplify check

* crypto: fix build

Fixes #15672 by creating the datadir when creating the
console. This prevents failing to save the history if no datadir
exists.

* swarm/api: url scheme bzz-list for getting list of files from manifest

Replace query parameter list=true for listing all files contained
in a swarm manifest with a new URL scheme bzz-list.

* swarm: replaace bzzr and bzzi schemes with bzz-raw and bzz-immutable

New URI Shemes are added and old ones are deprecated, but not removed.
Old Schemes bzzr and bzzi are functional for backward compatibility.

* swarm/api: completely remove bzzr and bzzi schemes

Remove old schemes in favour of bzz-raw and
bzz-immutable.

* swarm/api: revert "completely remove bzzr and bzzi schemes"

Keep bzzr and bzzi schemes for backward compatibility. At least
until 0.3 swarm release.

contracts/release: do not print error log if les backend has no peers

core/vm: Remove snapshot param from Interpreter.Run()

The tx data field is called "input" in returned objects and "data" in
argument objects. Make it so "input" can be used, but bail if both
are set.

accounts/keystore: Improved error message

* Fix for #15668

p2p/discover: fix leaked goroutine in data expiration

cmd/geth: add support for geth --rinkeby attach

This adds the inverse to DecompressPubkey and improves a few minor
details in crypto/secp256k1.

crypto: Fix comment typo

Fixes #15408
Fixes #14432

consensus/ethash: relax requirements when determining future-blocks

This commit adds mocker functionality to p2p/simulations. A
mocker allows to starting/stopping of nodes via the HTTP API.

This commit adds a TOML configuration option to swarm. It reuses
the TOML configuration structure used in geth with swarm
customized items.

The commit:

* Adds a "dumpconfig" command to the swarm executable which
  allows printing the (default) configuration to stdout, which
  then can be redirected to a file in order to customize it.
* Adds a "--config <file>" option to the swarm executable which will
  allow to load a configuration file in TOML format from the
  specified location in order to initialize the Swarm node The
  override priorities are like follows: environment variables
  override command line arguments override config file override
  default config.

With this change,

    key, err := crypto.HexToECDSA("000000...")
    
returns nil key and an error instead of a non-nil key with nil X
and Y inside. Issue found by @guidovranken.

Issue found by @guidovranken