Ensure linked app.configs are found

Ensure to find App.config files that are added to a project as a link
when looking for SpecFlow configuration sections.
Updated changelog with regards to fixed app.config issue.
Suggestion from aTEuCT, fix file watching

Incorporate suggested change by aTEuCT, ensure watching app.config for a
linked file still works.
Merge pull request #266 from ArildF/linked_appconfig

Linked appconfig