## Description
In blocks_results we use the proto definition of abciResponses: 2672b91ab0/rpc/core/blocks.go (L152-L155), this leads to the use of the proto definition of the pubkey which is an interface in go (oneof). The interface must be registered with the JSON encoder to have it work correctly.
A clearer divide between proto types and native types is needed.
Closes: #XXX
Reorganizes the Protobuf schemas. It is mostly bikeshedding, so if something is contentious or causes a lot of extra work then I'm fine with reverting. Some Protobuf and Go import paths will change.
* Move `abci/types/types.proto` to `abci/types.proto`.
* Move `crypto/keys/types.proto` and `crypto/merkle/types.proto` to `crypto/keys.proto` and `crypto/proof.proto`.
* Drop the use of `msgs` in filenames, as "message" is a very overloaded term (all Protobuf types are messages, and we also have `message Message`). Use `types.proto` as a catch-all, and otherwise name files by conceptual grouping instead of message kind.
