* Fix panic when dragging text onto a window on Windws (#697)
* Changed `panic` to `debug` (log) when unknow error occurs in `GetData` while processing a drag-drop / hover event. Plus added appropriate cursor effect if hovered item can not be processed.
* Improved code clarity.
* Add documentation to clarify behaviour of `DroppedFile`, `HoveredFile`, and `HoveredFileCancelled`
* Add period at the end of sentences in documentation.
* Implement HoveredFile and HoveredFileCancelled on Windows (#448)
* Update CHANGELOG.
* Applied code organizational corrections and fixed IDropHandler leak on window destroy.
* Moved FileDropHandle to a separate file.
