Minor bug in loss logging

Line 109 in `disvae/models/losses.py`:

```python
if not is_train or self.n_train_steps % self.record_loss_every == 1:
```

This does not work when self.record_loss_every is 1 (recording all mini-batches).

Fix:

```python
if not is_train or (self.n_train_steps - 1) % self.record_loss_every == 0:
```


 