complete getting started steps for OS X

You get 
`multirust: no default toolchain configured` 
when 
`multirust default stable`
is not executed.

Auto detect available port (with fixed test)

eth_getTransactionReceipt

Comprehensive tests for tracing transactions

Disable preparing work package if miners don't ask for it.

Listen on all interfaces for JSONRPC by default.

eth_estimateGas

Revert "Auto detect available port"

 Please enter the commit message for your changes. Lines starting

added output to execution result

Auto detect available port

Allow 0x prefix for --author.

updated dependencies, moved rpctest to its own submodule

use ethjson module to load chain json tests

Tracing implemented.