Simple calculator

1. type 'npm run dev' to run app locally with default parcel url: http://localhost:1234

2. type jasmine command at console to run the unit test

3. open index.html to open the calculator UI

4. Alternative way to start app is to click and open static.html file (static version)

features summary

1. chaining function is fully working, such as calc.add(6).add(5).subtract(1).multiply(2).divide(1).equals(); [It can be tested on part 1]

2. simple calculator major functionalities have been done [UI + Logic]

3. unit test for testing the (+-*/) major functions