* mobile: don't retain transient []byte in CallMsg.SetData

Go mobile doesn't copy []byte parameters, for performance and to allow
writes to the byte array be reflected in the native byte array.
Unfortunately, that means []byte arguments are only valid during the
call it is being passed into.

CallMsg.SetData retains such a byte array. Copy it instead

Fixes #14675

* mobile: copy all []byte arguments from gomobile

To avoid subtle errors when accidentially retaining an otherwise
transient byte slice coming from gomobile, copy all byte slices before
use.

* mobile: replace copySlice with common.CopyBytes

* mobile: Use EIP155Signer - closes #14762

* mobile: Correctly fall back on HomesteadSigner when no chainID is passed in

README: get rid of the non-existent disasm command

consensus/ethash, core: implement Metropolis EIP 100

Implements ethereum/EIPs#98

* core: remove redundant storage of transactions and receipts

* core, eth, internal: new transaction schema usage polishes

* eth: implement upgrade mechanism for db deduplication

* core, eth: drop old sequential key db upgrader

* eth: close last iterator on successful db upgrage

* core: prefix the lookup entries to make their purpose clearer

dockerignore: ignore all git metadata and all tests

Tests are now included as a submodule. This should make updating easier
and removes ~60MB of JSON data from the working copy.

State tests are replaced by General State Tests, which run the same test
with multiple fork configurations.

With the new test runner, consensus tests are run as subtests by walking
json files. Many hex issues have been fixed upstream since the last
update and most custom parsing code is replaced by existing JSON hex
types. Tests can now be marked as 'expected failures', ensuring that
fixes for those tests will trigger an update to test configuration. The
new test runner also supports parallel execution and the -short flag.

As stated in the documentation, this method should be called traceBlockFromFile
and not traceBlockByFile. Previously this would result in a 'The method ... does
not exist/is not available' error.

Txpool localaccounts

Refactor downloader to use interfaces instead of callbacks

The commit reworks the transaction pool queue limitation tests
to cater for testing local accounts, also testing the nolocal flag.

In addition, it also fixes a panic if local transactions exceeded
the global queue allowance (no accounts left to drop from) and also
fixes queue eviction to operate on all accounts, not just the one
being updated.

params: remove redundant consts, disable metro on AllProtocolChanges

This PR polishes the EIP 100 difficulty adjustment algorithm
to match the same mechanisms as the Homestead was implemented
to keep the code uniform. It also avoids a few memory allocs
by reusing big1 and big2, pulling it out of the common package
and into ethash.

The commit also fixes chain maker to forward the uncle hash
when creating a simulated chain (it wasn't needed until now
so we just skipped a copy there).

cmd/swarm: Exit if --ethapi is set