sha1crypt: report iteration count as tunable cost
broken/opencl_7z_fmt.c: tunable cost related fix

report iteration count as tunable cost and make sure
the tunable cost related changes don't cause compile errors...
scrypt format: report N, r, p as tunable costs

For now, this is just a q&d implementation

Problems: -copied decode64_one() and decode64_uint32()
           from escrypt/crypto_scrypt-common.c
           (Copyright 2013 Alexander Peslyak)
          -much of the logic in tunable_cost_[N|r|p] is identical
           and copied/adapted from escrypt_r() in
           escrypt/crypto_scrypt-common.c
           (Copyright 2013 Alexander Peslyak)

But I didn't feel like messing with Solar's optimized code,
e.g., removing the "static" keyword from decode64_one and
decode64_uint32, moving some of the re-used code into new
functions, etc.

OTOH, scrypt format is probably more important than django-scrypt.
So, not reporting tunable costs for scrypt is not an option.

The final implementation of the "tunable cost" stuff will probably
need an OK from Solar anyway.
Merge pull request #621 from frank-dittrich/bleeding-jumbo

Bleeding jumbo: more "tunable cost" changes