`py-indent-or-complete' modified

If `(region-active-p)' returns `t', indent region.
`py-split-windows-on-execute-p' renamed `py-split-window-on-execute-p'

There is just one window at stake

`py-toggle-split-windows-function' renamed `py-toggle-split-window-function'

py-split-window-on-execute-p default `t' restored
`py-unload-python-el', new command

Normally commands delivered by python.el are usable alongside with python-mode.el

However, there are skeletons hard-coded into python-mode-abbrev-table,
thus with abbrev-mode on, writing "if" unevitably triggers a skeleton
- IMO a bug, reported as #18841

In order to work around this, unload delivered shipped python.el.  M-x
`py-unload-python-el' RET will also remove python-skeleton forms from
abbrevs-file.
`py--complete-base' fixed WRT dedicated shells

`py-choose-shell' fixed
Require (interactive-p) when switching during tests
`py--complete-base', `py-choose-shell' fixed

Deal with versioned buffers python<n>
another-broken-font-locking-lp:961231-base fixed

font-lock reqired in any case

test/python-mode-test.el re-arranged
`py-help-at-point', don't leave temporary files
`py-shell-send-string' fixed

Don't leave temporary files
Error in menu-bar-update-hook, lp:801581, again
Indent after expect:, lp:1387329

fixed