Project Setup
Added CalculatorTestConvensionsAttribute
Exercise 1.  AddEmptyReturnsCorrectResults
Exercise 1. AddSingleNumberReturnsCorrectResult
Exercise 1. AddTwoNumbersReturnsCorrectResult
Exercise 2. AddAnyAmountOfNumbersReturnsCorrectResult
Exercise 3. AddWithLineBreakAndCommaAsDelimiterRetunrsCorrectResult
Exercise 4. AddLineWithCustomDelimiterRetunrsCorrectResult
Exercise 5. AddLineWithNegativeNumberThrowsCorrectException
Exercise 6. AddIgnoresBigNumbers
Exercise 7. AddLineWithCustomDelimiterStringReturnsCorrectResult
Exercise 8. AddLineWithMultipleCustomDelimiterStringsReturnsCorrectResult