project.pbxproj file is missing

When `ccv15/apps/addonsExamples/XCode/Community Core Vision.xcodeproj` is opened, it says:

```
Project ccv15/apps/addonsExamples/XCode/Community Core Vision.xcodeproj cannot be opened because it is missing its project.pbxproj file.
```

Any idea how to CCV's source code get working in Xcode?
