included capital gain taxes incured when withdrawing more than principal
included taxRate parameter in SavingsAccountYear methods to help in calculating capital gains taxes
Included tax withdrawn calculation in capitalGainsTaxIncurred

code as ending of session 7
Main cleanup of SavingsAccountYear and its test class
removed capitalGainsAmount field and substituted by a method calculation
added ending capital gains without implementation

code as session 9 ending
Consolidated nextYear and startingValues tests