Select content on drop, move selection to the end on paste

[Piotr Jasiun]

All application I tested have a different behavior for copy and paste and for drag and drop.

• After paste, caret is at the end of the pasted content (what makes sense, user most probably wants to start typing there).
• After drop, dropped content is selected (what also makes sense, because it may happen that user drops the content in not exactly correct position and wants to drag it again).

At the moment we always put the caret at the end, handle the drop in the "paste" way. The problem is that now insertHtml set the selection and this method does not know what operation causes insertion. Fortunately paste event has such information, so the selection should be done by paste event or information about the type of the selection should be passed to the insertHtml. The second way seems to be better because of backward compatibility.