* Added Account
* Updated FinancialTransactions
* Renamed FinancialTransactions.GetValue to GetValueOf
* It's now possible to get the balance of a certain month
* It's now possible to get the value of all transactions of a certain month
Added class for Year 
* Replaced all occurrences of "int year" with "Year year"
* Year can now implicitely converted to int and back
* Year.ToString outputs now the string of the value