Add bindings to verify_32 and verify_16

These provide constant time comparison operations for short strings of
32 and 16 bytes, respectively.  The relevent functions in this library
already use such comparisons (actually at the C level), but they are
exposed for completeness.
rbx now works on Travis, but ree doesn't

Even worse, ree breaks even if listed under allowed_failures
Hide libsodium build output

This hides the output of the libsodium build unless an error occurs, in
which case the full output is printed.

This should make it easier to read the build output in Travis
Security Notes
verify_(32/16) => verify(32|16)

To be a little more 'ruby like'
Merge pull request #13 from namelessjon/dev/verify

Add bindings to verify_32 and verify_16
Initial Ed25519 specs
Fix broken spec
Initial Ed25519 spike

This requires the new crypto_sign_publickey API in libsodium.

An initial spike of SigningKey/VerifyKey. Docs forthcoming.
Use Crypto::Random.random_bytes to generate Ed25519 keys
Upgrade to libsodium 0.2
Use crypto_sign_seed_keypair API to generate Ed25519 keys

This used the API found in libsodium 0.2
Fix spec that might be causing ruby-head failures

The goal of this spec was to produce a signature that looks similar but
is slightly off. This does the same thing by incrementing the value of
the first byte by one.
Crypto::VerifyKey#verify!

This provides an alternative API that raises an exception when a
signature fails to match, and signatures failing to match is certainly
an exceptional condition!
BadSignatureError < CryptoError

Since we have a "standard" CryptoError, use it
Move toplevel requires below module definition

This allows other code in the library to subclass Crypto::CryptoError
Merge pull request #12 from cryptosphere/ed25519

Ed25519 support
Usage outline and basic descriptions
Trying to improve readability with some rules
This one is probably unnecessary