Test all VKOs and KEGs to work and produce same keys for both parties.

Format: vko:<bit length>
Such as:
  vko:256 for VKO_256
  vko:512 for VKO_512
  vko:0   disable strict VKO mode, switch to other derive methods.

Suitable for tests. Use EVP_PKEY_CTRL_SET_VKO ctrl with appropriate
digest nid to enable VKO mode.

Standalone EC implementations from ECCKiila.

https://gitlab.com/nisec/ecckiila

* GOST key agreement cofactor fix

Bug found by Clang scan-build.

Fixes #258.

Fixes #257

openssl/openssl#11720 provided the necessary fix.

Test for conversion errors.

Such as, no need to run tests if build failed.

Also, allow verbose connect setting VERBOSE=1 env var.

All tabs replcaded with spaces. One file was 2 tabs fornating.

After registration rework many callbacks not need to be exported. Also,
some functions inconsistently declared static in headers and non-static
in the code. Finally, some functions just not need to be exported.

- Add year 2020 to old lines.
- Some files did not have original Copyright line - added "Update
  at 2020" to show that I'm not original contributor.
- Some files did not have License line - added reference to OpenSSL
  license.

Now only simple array of `GOST_digest's. No need to care about aliases
anymore.

Convert to a table method.

Covert their registration to table method.

Introduce `GOST_digest' to hold digest registration data, and
`GOST_init_digest'/`GOST_deinit_digest` helpers to handle it.

It's single-level templatized.

- Stream cipher should have block_size 1, other should not.
- Stream cipher should not have padding.
- If IV is specified Custom IV flag should be set.

Now we don't need a struct to hold cipher list. And can use simple array
of pointers to `GOST_cipher'.

Not needed after cipher registration converted into table way.

This only adds registering via tables, but not removing obsolete code.

Avoid duplication of struct values with help of 1-level templates.