AqFinance

Added modules for XML import and export of database.

With these modules it is now possible to dump a database to an XML
file (e.g. for backup purposes) and to read it back later.

This will also make it easier to provide a basic setup with currencies
and accounts.

More work on business module.

The business module can now manage open tasks. Invoices and payments can
now be added. Fixed a few bugs.

Improved interoperability with QBankManager.

- read category on import, create appropriate accounts if necessary
- FM_AccountAccPage now also rebuilds when AccountBalance changes
- FMAccountStmPage issues appropriate rebuild signals
- added widget FF_InvoiceTree (not yet finished)...

Listing open bills now works!

- added query functions "areset" and "isclear"
- added module AE_OpenBills
- removed unneeded code (ae_rollback)

More work on business code.

Icons resized.

Moved AE_Query code to database where we can use it also from within the database.

Currently we have two implementations of query code. This is the first step
in unification.

Started working on a business module. Use new icons.

Added preliminary business icon.

Work on build system.

Removed autogenerated files; sources are now created when necessary using
typemaker2. Removed unneeded files.