Mime types not respected with overlapping patterns

Qdirstat categorizes *.gz as a compressed file and a tar.gz as a compressed archive when looking at the mime categories. However, in practice, these files are both categorized as compressed files.  The same problem also occurs with user-defined Mime types. 


Minimal reproducible example:
```
mkdir test
cd test
echo "test" > test.tar.gz
echo "test" > test.gz
qdirstat .
```
 