Better log messages during notifications

### Description
Made underlying thread during notifications to have the same transactionId as its father.
Added LM_I 'Notification Sucessfully Sent' for notifications.
The changes should cover both ontimeinterval and onchange.

Fixes issue #453 

We have a lot of places with these too lines. Maybe we can use a function for that

```
terminateTrasaciton(transactionId)
```

```
void terminateTransaction(char* t)
{
   LM_I(("Transaction ended"));
   strncpy(transactionId, "N/A", sizeof(transactionId));
}
```

Actually, strncpy() needs sizeof(transactionId) taking into account that we know that "N/A" has a fixed size? C++ string arithmetic still anoyning me :)