New selection features, support for more navigation keys #300

This library looks very promising, thank you!

Here are a couple of desirable enhancement ideas that I can think of:

• Ability to move selected data
• Autofill (the cross that appears at the bottom right of a selection, and allows you to extrapolate the selected data)
• Support navigation keys (home, end, page up/down)

Feel free to split it into multiple tickets if needed, or argue that these features can be implemented at the user level.