Fix drag and drop from project to code editor.
Drag and drop to dataflow not fixed
Merge pull request #65 from gbaty/fix-drag-and-drop-data

Fix drag and drop from project to code editor.
Add sync method to allow to sync world manually (emit world_sync)
Display only datatype in browser
(value was dangerous for example with huge numpy arrays)
Merge pull request #66 from gbaty/improve-world

World improvement
Add service qt_container that generate a GUI to edit a group of controls
qt_container: use **kwargs instead of style for future features
Merge pull request #67 from gbaty/edit-multiple-controls

Add service qt_container that generate a GUI to edit a group of controls
First draft to integrate controls in notebook