Added AES, ZipAES and LZ4AES serializers, which does aes encryption, deflate compression + aes encryption and lz4 compression + aes encryption respectively.

- AES encryption is enabled by setting 'akka.actor.kryo.encryption = aes' and key used for encryption as 'akka.actor.kryo.aeskey = j68KkRjq21ykRGAQ'. By default encryption is set to 'off' and key as 'ThisIsASecretKey'
- For Zip + AES serialiser, data is first compressed and encrypted. Settings are: 'akka.actor.kryo.encryption = aes', 'akka.actor.kryo.aeskey = j68KkRjq21ykRGAQ' and ''akka.actor.kryo.compression = deflate'
- For lz4 + AES, settings are: 'akka.actor.kryo.encryption = aes', 'akka.actor.kryo.aeskey = j68KkRjq21ykRGAQ' and ''akka.actor.kryo.compression = lz4'