`py-pylint-offer-current-p' dropped as seems not worth the memory
usage

Keep python-mode as slim as reasonable.
If a buffer-file exists, it will be offered for check, otherwise
history is queried
Booleans `py-start-run-py-shell', `py-start-run-ipython-shell' dropped

Keep python-mode as slim as reasonable.
New command `py-report-comint-variable-setting', lp:1295002

Print values of comint-variables.
Used for debugging in "*Python*" shell buffer for example
New `py-object-reference-face', lp:1295087

Inherits default face, needs customization to be visible