Add Unstoppable Wallet to Wallet list

[esengulov]

Proposing to add Unstoppable wallet to a list of wallets, https://unstoppable.money

While Samourai has some advantages in privacy aspects the Green wallet significantly behind in most aspects. Give it a brief look, the wallet been in non-stop development for over 2.5 years, the GitHub has a full development record down to every single feature commit.

• https://github.com/horizontalsystems/unstoppable-wallet-android
• https://github.com/horizontalsystems/unstoppable-wallet-ios

The wallet listed as verified on WalletScrutiny as well as pending inclusion to Bitcoin.org

Built by https://horizontalsystems.io / https://github.com/horizontalsystems