Implement a Python-C binding to Soldity

Solidity has a JSON-based interface written in C to compiler contracts. The input is a JSON formatted list of contracts and the output is a JSON with bytecode, assembly, etc. (all the features of the commandline compiler).

This C interface (located in `solc/jsonCompiler.cpp`) could be used to write an FFI binding in Python. It is already compiled as a library (`libsoljson`).