Keyboard Events

Notes:

• Use on_control_key_down to intercept Unicode keys.
• Use on_control_key_action to intercept arrow keys, function keys home, end, page-up, page-down, insert, delete, etc..
• The constants ESC, BKSP, '\t' and '\n' are Unicode characters.
• The constants INS, DEL HOME, END, PGUP, PGDN, F1 through to F10, LEFT, RIGHT, UP and DOWN are non-Unicode key actions.