Enable Ledger Hardware Wallet support for Callisto (CLO)

EIP-155 is now properly working with Callisto!! Tested personally on the Ledger Nano S

    homepage           : https://callisto.network
    block explorer     : https://explorer.callisto.network
                       : https://cloexplorer.org
    network statistics : https://clostats.net
    slip0044 index     : 820
    chainId            : 820

Callisto has been unable to *safely* work with hardware wallets until the following changes were applied:
LedgerHQ/app-ethereum@8260268
LedgerHQ/app-ethereum@74c085c

Callisto has EIP-155 Replay attack protection enabled on their network.
For documentation of this, please see https://github.com/EthereumCommonwealth/go-callisto/blob/CLO/1.0/params/config.go

MyEtherWallet Full 32bit Chain ID support: (merged) MyEtherWallet#1979

Callisto is on Ledger's official roadmap:
https://trello.com/c/AawiAoSM/116-callisto-support

Ledger Nano S Full 32bit Chain ID support: (merged)
LedgerHQ/app-ethereum@8260268
LedgerHQ/app-ethereum@74c085c

Ledger Nano S Callisto (CLO) app: (merged)
LedgerHQ/app-ethereum#22

cc: @yograterol
cc: @project-callisto