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