#120 - Improvement of the autocompletion method. Prototyped the error messages for the status string.

The next step is to add the status string with the following error messages:
- [ ] Wrong path
- [ ] Wrong format
- [ ] File exists
- [ ] Loading path: %path%

Plus, disable "Create" button in case of issues which described above.

- Modified dynatree for a error notification in case of wrong path.