Initial commit of drag and drop using features and declarative functions.
Add types for drag drata
Remove unused event filter.
Call widget's mouseMoveEvent after custom mouseMoveEvent.
Fix order of drag_data default values.
Make Drag and Drop feature flags ORable.
Change drag data type from bytearray to str.
Add docstring to drag and drop example.
Pass DragEvent's to drag and drop functions so that data can be lazily fetched.
Merge pull request #161 from brett-patterson/drag-drop

Drag and drop