[WIP] debug_traceTransaction endpoint implementation

[pipermerriam]

Replaces: https://github.com/ethereum/py-evm/pull/1515 , removing all of the trinity components which will be added in a separate PR to the trinity repo once this is merged and released.

What was wrong?

https://github.com/ethereum/go-ethereum/wiki/Tracing:-Introduction

Adds support for tracing EVM transactions.

How was it fixed?

This adds a new API that can be used to trace transactions by supplying a tracer to VM.apply_transaction

Cute Animal Picture

[RaoulSchaffranek]

Are there any plans to continue the work on tracing?