* Update `github.com/ethereum/go-ethereum` package to 1.8.1 branch. Part of #638
* Fix code due to some signature changes. Part of #638
* use upstream for whisper backend
* Add patch to downgrade usage of Whisper v6 to v5 in some geth 1.8.1 vendor files. Part of #638
* Take into account the DNS rebinding protection introduced in 1.8.0 by adding exception for localhost. Part of #638
* Add patches required for cross-compiled builds starting with geth 1.8.0. Only applied during build. Part of #638
* Update expected JSON result in `TestRegressionGetTransactionReceipt()` and `TestCallRawResultGetTransactionReceipt()`. Part of #665
* Fix some failing e2e tests. Part of #638
* Address comments in PR #702. Part of #638
Network disconnect is introduced by removing default gateway, easily reversible condition.
On my local machine it takes 30 seconds for peers to reconnect after connectivity is restored. As you guess this is not an accident, and there is 30 seconds timeout for dial expiration. This dial expiration is used in p2p.Server to guarantee that peers are not dialed too often.
Additionally I added small script to Makefile to run such tests in docker environment, usage example:
```
make docker-test ARGS="./t/destructive/ -v -network=4"
```
Dmitry Shulyak
Pedro Pombeiro
Adam Babik
Dmitry Shulyak
Caner Çıdam
Igor Mandrigin