Merge pull request #54 from mpsonntag/filebrowser

Filebrowser
Generic bread crumb navigation

This should fix #55.

This class is completely untested but should be merged in order to use it in the file browser.
Merge pull request #57 from stoewer/gndata-editor-55

Generic bread crumb navigation
FileBrowser: Unstyled favorites
FileBrowser: Replace previous navigation with BreadCrumbNav