Type class aliases

[NickSeagull]

GHC doesn't support type class aliases. We should support a way through the source preprocessing to support type class aliases that are rewritten during compilation, not only in source code, but also in errors.

This would help making everything more homogeneous, like for example instead of having:

• Aeson.FromJSON/ToJSON
• Toml.FromValue/ToValue
• Protobuf.Encode/Decode

We could have

• Json.Decodable/Encodable
• Toml.Decodable/Encodable
• Protobuf.Decodable/Encodable

This supports the NeoHaskell principles of design