Add FileSystemTreeView (with basic file system operations: copy, cut, paste, deleted, copy path).
Move the widgets examples in a dedicated directory
Add a test directory structure for playing with the FileSystemTreeView
Fix bug when no context menu has been set yet
Fix usage of icon provider and fix a small attribute error bug if you're not using QCOdeEdit but QPlainTextEdit
Fix another attribute error
Merge branch 'master' into feature/filesystem_treeview
Fix drag & drop for non code edit widgets
Finish filesystem_treeview

Integrated into a internal at work, works nicely