Update formatting.
Disable the unicode for SDL2 key events.

The values are wrong so disable them for now.
Convert the GUI2 text API to take strings.

This change makes it easier to use the SDL2 text input events.
Implement the SDL2 text input event in GUI2.

This enables text editing in the GUI2 widgets.
Merge branch 'SDL2_GUI2_input'

Enable SDL2 text input in the GUI2 widgets.