Fixes bug of file exists with different mode

makedir is all manner of complainy if the dir already exists, but differs in its what it wants to default as for its mode bits. This just adds a quick/bad check to not even try to make the dir if it exists, thus skipping over makedirs chance to yell about 

```
FileExistsError: [Errno 17] File exists (mode 770 != expected mode 775): '~/.config/BioTK'
```