Bugfix: Catch IndexError on search results

There exist search results where the logic to collect `'history'` does not apply and fails with an `IndexError`. A first and simple approach to this issue is to `continue` on `IndexError` and ignore corrupted information of entries.

Change the following lines in `handelsregister.py`...

```python
113 for i in range(hist_start, len(cells), 3):
114 d['history'].append((cells[i], cells[i+1])) # (name, location)
```
...to:

```python
113 for i in range(hist_start, len(cells), 3):
114 try:
115 d['history'].append((cells[i], cells[i+1])) # (name, location)
116 except IndexError: # there might be entries where this logic does not apply
117 continue
```

Alternatively the author(s) should have another look at the results and the parsing.