Introduce response status errors

[cthulhu-rider]

Related #150.

Docs will be added right after structural finalization.

[alexvanin]

I think it is time to merge it finally.

[realloc]

Looks good in spec pdf

[carpawell]

Can you, please, clarify to me (not in code) how to interpret such common comments:

  // Statuses:
  // - **OK** (0, SECTION_SUCCESS):
  // balance has been successfully read;
  // - Common failures (SECTION_FAILURE_COMMON).

[cthulhu-rider]

@carpawell, common scheme is:

- <code_name> (<global_code>, <section_name>): <desc>

Сommon failures are special: they apply equally to all operations. It is inconvenient to copy them in manual mode, and there is no autogeneration, at least not yet. Therefore, the description of the codes of this section should be found in the place of their definition.