docs: Fixes #204. Update Readme. Add command to switch to Rust stable. Append binaries to installation command (#205)

* docs: Fixes #204

* Add command to switch to a stable version of Rust before installing Polkadot PoC-1 since error occurs when trying to install using Rust Nightly, which some users may have configured as their active toolchain
* Append ` polkadot subkey` to the command that installs the latest version of Polkadot PoC-1 to overcome error

* Update README.md

added the Rust version

* Fix initialisations and add a test.

* Fix test.

* Fix overflow bug.

* Minor refactoring and fixes.

* Fix vote threshold.

* Add note.

* Fixes for latest rust and the readme.

* Better readme.

* An extra validator for PoC-1

* Update README.

* PoC-1 bootnodes.

* don't return async::notready for messages without scheduling wakeup

* Fix endowed account

* give polkadot control over round proposer based on random seed

* address grumbles.