First official release!

This first release of libkeccak implements the SHA-3 algorithms (SHA3-224, SHA3-256, SHA3-384, and SHA3-512). The underlying primitives (e.g. the Sponge construction, the Keccak permutation) are highly customizable and can also be used to build customized hash functions (e.g. reduced rounds, smaller Keccak state size, etc...).