Optimised ANSI C code for the Rijndael cipher (now AES)

@authorVincent Rijmen <vincent.rijmen@esat.kuleuven.ac.be>
@authorAntoon Bosselaers <antoon.bosselaers@esat.kuleuven.ac.be>
@authorPaulo Barreto <paulo.barreto@terra.com.br>

This code is hereby placed in the public domain.

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