remove unused directories and update README (#145)

This change removes unused directories (`papers` and `research`) 
and updates the README to reflect our strategy for merging the 
informalsystems/tendermint-rs specs into this repository.

Partially addresses #121.

README.md

@@ -1,5 +1,25 @@
 # Tendermint Spec
 
-This repository contains specs of the current and future implementation of Tendermint the protocol, papers that have been published by the ICF or AIB and ongoing research in a variety of areas.
 
-- For the pdf, see the [latest release](https://github.com/tendermint/spec/releases).
+This repository contains specifications for the Tendermint protocol. For the pdf, see the [latest release](https://github.com/tendermint/spec/releases).
+
+There are currently two implementations of the Tendermint protocol, 
+maintained by two separate-but-collaborative entities:
+One in [Go](https://github.com/tendermint/tendermint), 
+maintained by Interchain GmbH, 
+and one in [Rust](https://github.com/informalsystems/tendermint-rs),
+maintained by Informal Systems. 
+
+There have been inadvertent divergences in the specs followed 
+by the Go implementation and the Rust implementation respectively. 
+However, we are worked to reconverge these specs into a single unified spec. 
+Consequently, this repository is in a bit of a state of flux.
+
+At the moment, the spec followed by the Go implementation 
+(tendermint/tendermint) is in the [spec](spec) directory, 
+while the spec followed by the Rust implementation 
+(informalsystems/tendermint-rs) is in the rust-spec
+directory. TLA+ specifications are also in the rust-spec directory.
+
+Over time, these specs will converge in the spec directory. 
+Once they have fully converged, we will version the spec moving forward. 

papers/README.md

@@ -1,5 +0,0 @@
-# Papers
-
-This folder houses Papers that have either been published or are a work in progress.
-
-## Table of Contents

research/README.md

@@ -1,5 +0,0 @@
-# Research
-
-This folder holds ongoing research and topics of interest. The [Interchain Foundation](https://interchain.io) has research topics that they are willing fund the research for, to find out more you can go to there [funding repo](https://github.com/interchainio/funding/blob/master/research.md).
-
-You can apply for a research grant [here](https://docs.google.com/forms/d/e/1FAIpQLSclH4R5G7WgNpKPvXxPPFRA7rAoyX8nNvsJAQJpZNZwWWjFmA/viewform)