Merge pull request #52 from CLEARCORP-dev/7.0_sale_commission_gs

[FIX] - Fixed module to use the payment due date instead of the current date to calculate due date.
[IMP] - account_banking_ccorp: Currency code from company.

Improved method to gather the default currency code from company.
Merge pull request #53 from CLEARCORP-dev/7.0_account_banking_ccorp

[IMP] - account_banking_ccorp: Currency code from company.
[IMP] - account_banking_ccorp: Added improved error messages.
Merge pull request #54 from CLEARCORP-dev/7.0_account_banking_ccorp

[IMP] - account_banking_ccorp: Added improved error messages.
[FIX] - Modified the total sales calculation to used the amount discounted instead of the total amount.