sort registered engines before detection
sort registered engines before detection

Make sure the registered engines are sorted by key to prevent injecting banks at varioius orders and not having the detection adhere to the injected order...

This allows:
```php
$mt940::registerEngine('BankMiddle', 1000);
$mt940::registerEngine('BankLast', 1001);
$mt940::registerEngine('BankFirst', 900);

// $registeredEnginesOrderDuringDetection = ['BankFirst', 'BankMiddle', 'BankLast']
```

fixes #39 Thanks for the catch @frans-beech-it

fruitl00p/php-mt940