Merge pull request #391 from haukepetersen/import_crypto

sys/Makefile

sys/crypto/3des/3des.c

sys/crypto/3des/Makefile

sys/crypto/Makefile

sys/crypto/aes/Makefile

sys/crypto/aes/aes.c

sys/crypto/doc.txt

sys/crypto/rc5/Makefile

sys/crypto/rc5/rc5.c

sys/crypto/sha256/Makefile

sys/crypto/sha256/sha256.c

sys/crypto/skipjack/Makefile

sys/crypto/skipjack/skipjack.c

sys/crypto/twofish/Makefile

sys/crypto/twofish/twofish.c

sys/include/crypto/3des.h

sys/include/crypto/aes.h

sys/include/crypto/cbcmode.h

sys/include/crypto/ciphers.h

sys/include/crypto/rc5.h