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"

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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.

test ethjson module on travis