Blowfish doesn't have proper init method for bcmode objects

[MatthewScholefield]

When running the CFB example in the repo with blowfish, ectx.init(key, iv) fails in template instantiation because ctx.cipher.init(unsafeAddr key[0]) doesn't exist for blowfish. Due to its variable key size, it requires an alternative init call of ctx.cipher.init(unsafeAddr key[0], keySize). This is currently provided by initBlowfish(), and init(_: var BlowfishContext, ...) but not for things like init(_: var CFB[BlowfishContext], ...). Since cipher is private in all of the bcmode objects, I don't think there's a way to properly initialize them.