Fix unintentional breaking API change in `Serializer`/`Deserializer` (#128)
Fix unintentional breaking API change in `Serializer`/`Deserializer` (#128)

While introducing selectable endianness in
https://github.com/TyOverby/bincode/pull/103 , the new type parameter
has been hidden from the public `serialize()`, `deserialize()` etc.
functions, and only made available through an alternate API entry point.
The same kind of encapsulation also needs to be performed for the public
`Serializer` and `Deserializer` types.
servo/bincode,TyOverby/bincode