[RFC] Gost algorithms implementation

This is an RFC providing not yet finished implementation/port of GOST algorithms suite from old OpenSSL codebase. Please review and possibly comment. I remember that final submission should be in a form of CVS patch, I just wanted to share my current progress and receive feedback.

There are still some fixmes and commented out parts, I will sort them away later.
I'm also unsure about using md_ctrl callback - it is (nearly) unused in the rest of the code (two ctrls defined,
one completely unused, one used only in asn_mime code, no message digests actually provide the callback) and looks like a perfect candidate for removal.

## Algorithms

- [x] GOST 28147-89 cipher
- [x] GOST 28147-89 ECB
- [x] GOST 28147-89 CFB
- [x] GOST 28147-89 CNT
- [ ] GOST 28147-89 CBC (per rfc4357)
- [x] GOST 28147-89 IMIT (MAC mode)
- [ ] GOST R 34.10-94 (obsolete digital signatures)
- [x] GOST R 34.10-2001 (digital signatures)
- [x] GOST R 34.10-2012 (new digital signatures)
- [x] GOST R 34.11-94 (message digest)
- [x] GOST R 34.11-2012 (Streebog, new message digest)

## Use cases

- [ ] X.509 vs GOST R 34.10-94/GOST R 34.11-94 (obsolete)
- [ ] CMS vs GOST R 34.10-94/GOST R 34.11-94 (obsolete)
- [ ] TLS vs GOST R 34.10-94/GOST R 34.11-94 (obsolete)
- [x] X.509 vs GOST R 34.10-2001/GOST R 34.11-94
- [x] CMS vs GOST R 34.10-2001/GOST R 34.11-94
- [x] TLS vs GOST R 34.10-2001/GOST R 34.11-94
- [x] X.509 vs GOST R 34.10-2012/GOST R 34.11-2012
- [x] CMS vs GOST R 34.10-2012/GOST R 34.11-2012
- [x] TLS vs GOST R 34.10-2012/GOST R 34.11-2012