* core/types: make Signer derive address instead of public key
There are two reasons to do this now: The upcoming ethclient signer
doesn't know the public key, just the address. EIP 208 will introduce a
new signer which derives the 'entry point' address for transactions with
zero signature. The entry point has no public key.
Other changes to the interface ease the path make to moving signature
crypto out of core/types later.
* ethclient, mobile: add TransactionSender
The new method can get the right signer without any crypto, and without
knowledge of the signature scheme that was used when the transaction was
included.
As per #14661 TransactionByHash always returns false for pending.
This uses blockNumber rather than blockHash to ensure that it returns
the correct value for pending and will not suffer side-effects if
eth_getTransactionByHash is fixed in future.
There is no need to depend on the old context package now that the
minimum Go version is 1.7. The move to "context" eliminates our weird
vendoring setup. Some vendored code still uses golang.org/x/net/context
and it is now vendored in the normal way.
This change triggered new vet checks around context.WithTimeout which
didn't fire with golang.org/x/net/context.
This significantly reduces the dependency closure of ethclient, which no
longer depends on core/vm as of this change.
All uses of vm.Logs are replaced by []*types.Log. NewLog is gone too,
the constructor simply returned a literal.
ethclient now returns ethereum.NotFound if the server returns null and
no error while accessing blockchain data.
The light client cannot provide arbitrary transactions. The change to
split transaction access into its own interface emphasizes that
transactions should not be relied on and recommends use of logs.
ethclient implements the proposed Ethereum Go API. There are no tests at
the moment, a suite that excercises all implementations of the API will
be added later.
