* lisp/progmodes/python.el (python-shell-buffer-substring): Handle
cornercase when region sent starts at point-min.
Merge from origin/emacs-24

433af0a * lisp/progmodes/python.el (python-shell-buffer-substring): Handle cornercase when region sent starts at point-min.
python.el: Enhance shell user interaction and deprecate python-shell-get-or-create-process.

* lisp/progmodes/python.el
(python-shell-get-process-or-error): New function.
(python-shell-with-shell-buffer): Use it.
(python-shell-send-string, python-shell-send-region)
(python-shell-send-buffer, python-shell-send-defun)
(python-shell-send-file, python-shell-switch-to-shell): Use it.
Add argument MSG to display user-friendly message when no process
is running.
(python-shell-switch-to-shell): Call pop-to-buffer with NORECORD.
(python-shell-make-comint): Rename argument SHOW from POP.  Use
display-buffer instead of pop-to-buffer.
(run-python): Doc fix.  Return process.
(python-shell-get-or-create-process): Make obsolete.

* test/automated/python-tests.el (python-shell-get-or-create-process-1)
(python-shell-get-or-create-process-2)
(python-shell-get-or-create-process-3): Remove tests.
Handle nil value of suggest-key-bindings

* lisp/simple.el (execute-extended-command):
When `suggest-key-bindings' is nil, don't.
* test/automated/let-alist.el: Load dependency.
(elisp--xref-identifier-file): Skip features that have no sources

* lisp/progmodes/elisp-mode.el (elisp--xref-identifier-file):
Skip features that have no sources.
python.el: Native readline completion.

This commit adds native readline completion that fallbacks to the old
mechanism when it cannot be used for the current interpreter.

* lisp/progmodes/python.el (python-shell-completion-native-disabled-interpreters)
(python-shell-completion-native-enable)
(python-shell-completion-native-output-timeout): New defcustoms.
(python-shell-completion-native-interpreter-disabled-p)
(python-shell-completion-native-try)
(python-shell-completion-native-setup)
(python-shell-completion-native-turn-off)
(python-shell-completion-native-turn-on)
(python-shell-completion-native-turn-on-maybe)
(python-shell-completion-native-turn-on-maybe-with-msg)
(python-shell-completion-native-toggle): New functions.
(python-shell-completion-native-get-completions): New function.
(python-shell-completion-at-point): Use it.

* test/automated/python-tests.el
(python-shell-completion-native-interpreter-disabled-p-1): New
test.