## Description
This PR removes simple prefix from all types in the crypto/merkle directory.
The two proto types `Proof` & `ProofOp` have been moved to the `proto/crypto/merkle` directory.
proto messge `Proof` was renamed to `ProofOps` and `SimpleProof` message to `Proof`.
Closes: #2755
* crypto: revert to mainline Go crypto lib
We used to use a fork for a modified bcrypt so we could pass our own
randomness but this was largely unecessary, unused, and a burden.
So now we just use the mainline Go crypto lib.
* changelog
* fix tests
* version and changelog
Currently the top level directory contains basically all of the code
for the crypto package. This PR moves the crypto code into submodules
in a similar manner to what `golang/x/crypto` does. This improves code
organization.
Ref discussion: https://github.com/tendermint/tendermint/pull/1966Closes#1956
