Improve Python editor (including fixing PAL7231) as follows:
1) process keyboard actions for the following keys: <up>, <down>, <left>, <right>, <pgup>, <pgdown>, <home>, <end>, <delete>, <backspace>, <insert> with different key-modifiers like <Ctrl>, <Shift>.
2) process pasting of selected text to the command line by middle-button mouse click (works also for external selection).
3) process drop event: paste dragged text to the command line.
See PAL7231 additional comments from 10/01/05 for more details.
