Normalisation of real numbers does not work

Note: this issue completes issue #50 that was covering several problems including this one.

When analysing "123 45.6 . 12 345.6", we should get three number entities with the correct numeric values:

- 123
- 45.6
- 12345.6

But we get (simplified):
```
Numex.NUMBER
123 45.6
0

Numex.NUMBER
12 345.6
0
```

The changes on branch https://github.com/aymara/lima/tree/AutomatonTransitionOnDouble try to handle the two problems of correctly recognizing the entities and correctly normalizing them. But for an unknown reason, the changes do not work as expected.