Add Asset & Liability banking (Mortgages and Loans)

Enhancements

• Add Other Asset (e.g. for Loans to other people) and Other Liability (e.g. for mortgages) account types to banking.
• Change "Cheque" to "Withdrawal" throughout, as few people use cheques any more.
• Improved QIF import to cope with more versions of Quicken/Quick Books