ConvertApp: This is a simple currency converter app. Its uses data from free, public api to download rates to calculate desired rate in selected currency. Default currency is `GBP` with amount of 100.0. Contains: - soure code for the app in `PaymentApp` folder - unit tests in `PaymentAppTests` folder Usage: - main view presents downloaded rates in collectionView with `GBP` as default currency - each cell show a flag, short annd long currency name and input - input can be used to provide given amount of money - each time user begins to edit that amount, its cell moves to the top - currencies are refresh on a timer, every 2 seconds with initial 2 seconds delay