New boolean `py-max-help-buffer-p'

If "*Python-Help*"-buffer should appear as the only
visible.

Default is nil, as beginners might get confused.
C-u TAB allow any forced indent, lp:1251824

fixed
`py-beginning-of-statement' fixed, lp:1252029

In interactive mode, limit (syntax-ppss) to previous prompt.

Otherwise previous output or banner will mess up results
`py--narrow-in-comint-modes' new function

will be needed not just by `py-beginning-of-statement'
`py--shell-make-comint' new function

Make `py-shell' a little bit easier to read
`py--shell-setup' new function

`py-shell' readability again
`py--init-easy-menu' new function

Readability of `python-mode-map' settings
`py-execute-buffer-ipython', lp:1252643

fixed
`py-complete-or-indent', new command

If after symbol-characters, try to complete, otherwise indent. 

This was requested from users coming from other
editors. Intend to provide it as an option.
Default of `py-indent-no-completion-p' set to nil

Set up py-complete-function in py-shell