FIXED: CPSegementedControl with nib2cib crashes

When having a CPSegmentedControl within a a XIB files, nib2cib crashes with the following error:

```
'undefined' is not an object (evaluating 'self._themeStates[aSegment].without')
```

This pull request fixes the problem by making sure that the drawBezel method is called with a valid segment index when accessing the themeState.

Reduction: https://dl.dropboxusercontent.com/u/14629300/BugCPSegmentedControl.zip