All the functions must start returning a status.

[martun]

Every time marshalling happens, we receive a status: "nil::marshalling::status_type status".
We must stop ignoring these statuses, because someone may intentionally give us a wrong structure on input.
We can not use throw/catch in our code, since we want to keep the potential ability to compile crypto3 code into an EVM bytecode.

So far the best solution is to propagate these statuses up through all the functions, which will require lots of code changes.