Alpha release v0.0.5

This is a pre-alpha point release of the Tari base layer. The following summary only includes major updates since the
last release.

_Note:_ This is the first point release since 0.0.2.

** Blockchain updates

Most of the major pieces of the blockchain implementation are in place, though the wiring between the pieces is still
outstanding.

* Blockchain database API. A backend-agnostic implementation of the Blockchain DB is included in`chain_storage`
* Tari mempool implementation is included. See `base_layer/core/mempoool`
* Bulletproof Range proofs
* Benchmarks for bulletproofs
* Basic wallet functionality, including key management and signature capabilities. See `base_layer/wallet`
* Placeholder Blake2b-based proof-of-work algorithm included. Tari will be merge-mined with Monero, but for testing/
  testnet purposes we have a Blake2b-based PoW implementation.
* A backend-agnostic Merkle Mountain Range implementation; including "mutable" MMRs and MMR checkpoints. The
  `merklemountainrange` crate has been deprecated.
* A rewrite of the LMDB-backend in `infrastructure/storage`

** Communications stack

Tari is built on a completely server-less, peer-to-peer communications network using distributed hash tables (DHT) and
public key infrastructure (PKI).

* The Tari communication stack is in Alpha. We're currently working on performance and stabilisation improvements.
* DHT service implemented for Tari node discovery and peer-to-peer communication
* Migrating the comms stack to use `futures-0.3` is underway.
* A Ping-pong test application. See `base_layer/p2p/examples/pingpong.rs`.
* CLI text messenger demo application. See `applications/console_text_messenger`.

** Documentation

* Several RFC documents have been put into draft stage. See https://rfc.tari.com.
* Many RFC editing fixes

v0.0.1