Adjusted broke sequence and unit test to illustrate a lingering error

unit test fails when I remove broke.0002 and change the assertion to be:
```python
self.assertEquals("0000-0001,0004,0006-0008", seq.format("{range}"))
self.assertEquals("broke.0000-0001,0004,0006-0008#.exr", seq.format())
```

gives
```
"AssertionError: '0000-0001,0004,0006-0008' != '0000,0001,0004,0006-0008'"
``