Add currency computation package (#2524)

* github.com repo: [currency](https://github.com/bnkamalesh/currency)

godoc.org: [![](https://godoc.org/github.com/nathany/looper?status.svg)](https://godoc.org/github.com/bnkamalesh/currency)

goreportcard.com: [![](https://goreportcard.com/badge/github.com/bnkamalesh/currency)](https://goreportcard.com/report/github.com/bnkamalesh/currency)

coverage service: [cover.run](https://cover.run/go/github.com/bnkamalesh/currency)

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* added period at end of description.

README.md

@@ -631,6 +631,7 @@ Please take a quick gander at the [contribution guidelines](https://github.com/a
 *Packages for accounting and finance.*
 
 * [accounting](https://github.com/leekchan/accounting) - money and currency formatting for golang.
+* [currency](https://github.com/bnkamalesh/currency) - High performant & accurate currency computation package.
 * [decimal](https://github.com/shopspring/decimal) - Arbitrary-precision fixed-point decimal numbers.
 * [go-finance](https://github.com/FlashBoys/go-finance) - Comprehensive financial markets data in Go.
 * [go-finance](https://github.com/alpeb/go-finance) - Library of financial functions for time value of money (annuities), cash flow, interest rate conversions, bonds and depreciation calculations.