"TypeError: String required"

I get following error when trying to convert camel case text to underscore:

> Traceback (most recent call last):
> File "...\Sublime3\sublime_plugin.py", line 818, in run_
> return self.run(edit)
> File "...\Sublime3\Data\Packages\StringUtilities\stringutilities.py", line 117, in run
> self.view.replace(edit, region, text)
> File "...\Sublime3\sublime.py", line 823, in replace
> sublime_api.view_replace(self.view_id, edit.edit_token, r, text)
>TypeError: String required

The real issue happens here:

https://github.com/akalongman/sublimetext-stringutilities/blob/master/stringutilities.py#L116

This code may set the variable `text` to a boolean value, which triggers the "TypeError: String required".

This code may be fixed by replacing it by:

```python
if '_' in text and text[0].islower():
text = self.toCamelCase(text)
else:
text = self.toUnderscores(text)
```