libsodium 0.6.1

Fixes #45 - Mostly, there's one broken unit test, need to see what the
issue is. Is the test wrong, or did something change on the libsodium
side.
Removed test

Test was removed from upstream:
https://github.com/jedisct1/libsodium/commit/2058eaea999b336fad108999638b3bd5302a96a3
Merge pull request #47 from adamcaudill/ilbsodium_v061

libsodium 0.6.1
Introducing PasswordHash

Implementation of crypto_pwhash_scryptxsalsa208sha256_str
crypto_pwhash_scryptxsalsa208sha256_str_verify
and crypto_pwhash_scryptxsalsa208sha256
Including interop runtime namespace
Including PasswordHashTest
Removing constructor
add SCRYPT_SALSA208_SHA256_BYTES const
Implement crypto_pwhash_scryptxsalsa208sha256 x64
Implement crypto_pwhash_scryptxsalsa208sha256_str x64
Implement crypto_pwhash_scryptxsalsa208sha256_str_verify x64
Implement crypto_pwhash_scryptxsalsa208sha256 x86
Implement crypto_pwhash_scryptxsalsa208sha256_str x86
Implement crypto_pwhash_scryptxsalsa208sha256_str_verify x86
Removing constructor, adding TestFixture attr