Fix QType Cast Double value to Integer value bug.

PHP Allows us to cast double values to integers quite easily. Assuming the double value to be ```4.4519452160494```, the following code will cast the value to 4:

```
$dblValue = 4.4519452160494;
$intValue = (int)$dblValue;
```

However, when we do:

```
$dblValue = 4.4519452160494;
$intValue = QType::Cast($dblValue, QType::Integer);
```
We get an error. This is because we are checking for only 'digits' when the conversion from old format to new and back does not yield the same result. The current change tries to fix this.