Initial checking of Tk-based Python IDE.
Features: text editor with syntax coloring and undo;
subclassed into interactive Python shell which adds history.
diff --git a/Tools/idle/help.txt b/Tools/idle/help.txt
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+Windows and files:
+
+ ^X ^N creates new empty text editor window
+ ^X ^C closes all windows
+ Alt-F4 or ^X ^0 (that's control-x-control-zero) closes current window
+ ^X ^D opens a file from dialog box
+ ^X ^S saves to current file
+ ^X ^W saves to file from dialog box
+ ^X w save a copy to file from dialog box
+
+Navigation:
+
+ Arrow keys and Page Up/Down to move around
+ Home/End go to begin/end of line
+ Control-Home/End go to begin/end of file
+ Some Emacs bindings may also work, e.g. ^A/^E
+
+Searching: all searches are forward from the cursor without
+wrap-around, case sensitive, Perl-style regular expression matches
+
+ ^S without a selection opens search dialog box
+ ^S with a selection searches for selected text
+ ^U ^S repeats last search
+ Alt-G opens dialog box to go to a specific line
+
+Editing:
+
+ Backspace deletes left of cursor, Delete right of cursor
+ Cut and paste use platform's conventions
+ ^[ or Alt-[ left-shifts (dedents) the current line or selection
+ ^] or Alt-] right-shifts (indents) the current line or selection
+ Alt-/ expands last word you type (like Emacs dabbrev)
+
+Undo:
+
+ ^Z undoes last change; repeat to undo more
+ Alt-Z redoes last undone change; repeat to redo more
+
+Console window:
+
+ ^C interrupts executing command
+ ^D sends end-of-file; closes console if typed at >>> prompt
+
+ If you get a traceback, right-click on any line listing a
+ filename and line number and select "Go to line from
+ traceback" to open that file and go to the indicated line
+
+Python syntax colors: the coloring is applied in a background thread
+
+ Keywords orange
+ Strings green
+ Comments red
+ Definitions blue
+
+Console colors:
+
+ Console output red
+ stdout blue
+ stderr dark green
+ stdin purple