Importing direct debit receipts Merged

Having the ability to import a sales ledger receipt separate from the bank import function would allow for a more accurate importing of direct debit collections, specifying the sales ledger account to import to as part of the import. This file would ideally be auto-generated within fee billing in the correct format.

Additional functionality about auto-allocating of direct debits would be useful as well, such as allocating all accounts when importing if the final value becomes zero, with option to manually allocate when account balance is not zero, or just to auto-allocate to oldest items (ie. a suggested allocation screen be given as part of the import process).