Cryptocoin rates API wrapper

[Renat.Su]

So, I filled in a small new repository. Under my unit for parsing the exchange rate from the Central Bank of RF and a new unit for parsing the cryptocurrency exchange rate, the repository was filled in, as it may also be useful to someone https://github.com/Al-Muhandis/CurrencyRates

It works simply. In order not to break into servers with their own limits in parallel, I made a thread-safe global objects: _CryptoCompare (for cryptocurrencies) / _CBRValutes (CBR), which update information as necessary (each time they do not knock on the server, but cache data in memory). The class is simple, improvements, criticism and new wrappers are welcome. Each unit is independent and can be used separately.