Fix a bug where we would use the wrong xml documentation file.

This can happen when multiple .xml files are in target directory.
For example when we have the following files in a directory:
```
Project.dll
Project.Hosts.Console.xml
Project.xml
```
It could happen that we use ```Project.dll``` with ```Project.Hosts.Console.xml```.
To provide the old behavior I first try to find an exact match and then fall back to the old code (should I remove that?)