upgrade aes and cfb8 crates from 0.7 to 0.8

[dyc3]

Right now, the unit tests for this will fail. Do not merge this as is, it will break clients being able to connect.

There are some breaking changes moving from 0.7 to 0.8. Namely, the cfb8 crate now provides 2 types Encryptor<T> and Decryptor<T> and the encrypt() and decrypt() methods now consume the cipher instead of just borrowing it. (eg. fn encrypt(self, ...) rather than fn encrypt(&self, ...))

I'm putting this up as a draft so somebody else can pick it up if I don't get back around to it.

[rj00a]

the encrypt() and decrypt() methods now consume the cipher instead of just borrowing it

That's the problem. The state of the cipher is supposed to change over time as new data comes in. How are we supposed to do that if the cipher is consumed in one go?

[rj00a]

Closing this since packet encoder/decoder was rewritten in #146 and will be again soon. However, the issue still remains.