Add unitdp to queries

Added unitdp param to allow the return of up to 4 decimal points on
- invoices
- overpayments
- banktransactions
- prepayements
- receipts
- items

Add more missing ValidationError array

Account
BankTransaction
BankTransfer
CreditNote
Item
LinkedTransaction
ManualJournal
Payment
PaymentService
PurchaseOrder

Fixed tracking for ManualJournal Line items

Added missing TrackingOptionId and Option string

Update for 2.3.1

Add CISOrgSetting for UK orgniasations
Add ValidationErrror array missing from Invoices
Change updatePayment method to deletePayment since all you can do is reverse a payment by updating the status.  Payments cannot be modified, only created and deleted.

fix user list

Fix issue by removing sample config.json files

Feedback that config.json files included in the SDK causing problems - need to update Test cases to use a CustomJsonConfig  instead.

Add missing Payment property on Credti Note Object

Fix Payment Terms on Contact

Payment Terms incorrectly set to PaymentTerm Type, when it should be a PaymentTerm object on a Contact.

missing semi-colon;

update pom.xml