Database.php :
* Change account order
* Forgot $db variable in LoadCategory
User.php :
* Add default category for index 0
index.php :
* Initialize $categories and $accounts arrays
* Typo error for hidden accounts
* Forgive credit on blocked account
* Forgot to divide amounts by 100
* Forgot to initialize tr_class variable in some case
* QString::number use scientific format, si it's invalid for numbers > 1 000 000. We need to use v.sprintf("%d");
* Accounts and categories where badly mapped during import
* Fix cost not taken in account during import
* Forbid empty account name and empty category name
