Extract additional information from MCInst

[stuxnot]

The MCInst holds additional information about the instruction, like mnemonic and operands. Using smth like

for (int i = 0; i < insn.getNumOperands(); ++i) {
    std::string op_str;
    llvm::raw_string_ostream op_stream(op_str);
    auto oper = insn.getOperand(i);
    oper.print(op_stream, register_info.get());
}

(or similar) should enable the instruction details to hold more information.

[stuxnot]

Duplicate of #34.