accounts/abi/bind: support closing a simulated backend

This change ensures 'blockHash', 'blockNumber' and 'transactionIndex'
are set to null for pending transactions. This behavior is required by
the Ethereum JSON-RPC spec.

* Fixes #19861 - coloured output

* cmd/clef: minor formatting nit

* cmd/clef: bleah, stupid github editor

* eth, interal, les: add getHeaderBy* APIs

* internal: address the comment

* eth, internal, les: getHeader nits, missing TD, console callable

* bump azure-storage-blob-go dependency to 0.3.0 release

* update azure-storage-blob-go module import path

* fix multiple return values on azblob.NewSharedKeyCredential

* vendor: bump Azure libs to latest from upstream

cmd/geth: skip 4GB memory bump for devnet

* Add 5 minute grace period to faucet timeout

* cmd/faucet: make grace period dynamic based on original wait time

Fixed assigning values to variables we don't end up using.

* rpc: implement websockets with github.com/gorilla/websocket

This change makes package rpc use the github.com/gorilla/websocket
package for WebSockets instead of golang.org/x/net/websocket. The new
library is more robust and supports all WebSocket features including
continuation frames.

There are new tests for two issues with the previously-used library:

  - TestWebsocketClientPing checks handling of Ping frames.
  - TestWebsocketLargeCall checks whether the request size limit is
    applied correctly.

* rpc: raise HTTP/WebSocket request size limit to 5MB

* rpc: remove default origin for client connections

The client used to put the local hostname into the Origin header because
the server wanted an origin to accept the connection, but that's silly:
Origin is for browsers/websites. The nobody would whitelist a particular
hostname.

Now that the server doesn't need Origin anymore, don't bother setting
one for clients. Users who need an origin can use DialWebsocket to
create a client with arbitrary origin if needed.

* vendor: put golang.org/x/net/websocket back

* rpc: don't set Origin header for empty (default) origin

* rpc: add HTTP status code to handshake error

This makes it easier to debug failing connections.

* ethstats: use github.com/gorilla/websocket

* rpc: fix lint

all: update author list and licenses

params: bump hard-coded CHTs to 22nd July values

* Added missing error checks

Add error handling where we assign err a value, but don't check for it being nil.

* core/rawdb: tiny style nit

No need to convert these types.

internal/ethapi: fix debug.chaindbProperty

core: check error before accessing potentially nil block

* signer/core: fix reference issue in key derivation

* Review feedback

* core: fix write coucurrency in txpool

* core: add rlock for pendingState read access

* core: address comments

Gollvm has very aggressive dead code elimination that completely
removes one of these two benchmarks.  To prevent this, use the
result of the benchmark (a boolean), and to be "fair", make the
transformation to both benchmarks.

To be reliably assured of not removing the code, "use" means
assigning to an exported global.  Non-exported globals and
//go:noinline functions are possibly subject to this optimization.

This adds the debug_accountRange method which returns all accounts in
the state for a given block and transaction index.