Compiling latest version fails with missing file

```
15:44:36 clang: error: no such file or directory: '/Users/sydneyerickson/.jenkins/workspace/NightShiftUnlocker/NightShiftUnlocker/OSVersion.cpp'
15:44:36 clang: error: no input files
```

I saw that the file got removed in the 2.0 commit. Perhaps it's still needed, or wasn't removed fully from the project?