Backport commits to beta (#1763)

* Don't try to sync to ancient blocks

* Parallel block body download

* Fixed reading chunked EIP8 handshake (#1712)

* Fixed reading chunked EIP8 handshake

* Added missing break

* Disconnect peers on a fork

* Updated json-ipc-server

* Combine mining queue and enabled into single locked datum (#1749)

* Combine mining queue and enabled into single locked datum

Additional tracing.

* Fix bug uncovered by test.

* Fix typo

* Remove unneeded log initialisation in test.

* fix failing test (#1756)

* Fixed test

* Suicides tracing (#1688)

* tracing suicide

* fixed #1635

* fixed typo

* Stackoverflow #1686 (#1698)

* flat trace serialization

* tracing finds transaction which creates contract

* flatten traces before inserting them to the db

* Trace other types of calls (#1727)

* Trace through DELEGATECALL and CALLCODE

Add them to the JSON output and RLP database store.

* Fix tests.

* Fix all tests.

* Fix one more test.

* filtering transactions toAddress includes contract creation (#1697)

* tracing finds transaction which creates contract

* comma cleanup

Remove when following `}`s, add to final entries.

* Various improvements to tracing & diagnostics. (#1707)

* Various improvements to tracing & diagnostics.

- Manage possibility of `Account` not having code for `PodAccount`
- New RPC: `trace_sendRawTransaction`
- See raw transaction dump when inspecting over RPC

* Fix test

* Remove one of the dupe error messages

* Remove unneeded `&`s

* Reformat and extremely minor optimisation

* Minor optimisation

* Remove unneeded let

* Fix tests.

* Additional fix.

* Minor rename.

* Bowing to the pressure.

* Stackoverflow fix (#1742)

* executive tracer builds flat traces without intermediate struct

* temporarilt commented out tests for traces

* fixed new way of building trace address

* fixed new way of building trace address

* updating state tests with flat tracing in progress

* fixed flat tracing tests

* fixed compiling ethcore-rpc with new flat traces

* removed warnings from ethcore module

* remove unused data structures