Unused boolean `py-paragraph-fill-docstring-p' removed

Exists `py-fill-paragraph' and the py-fill-string-... commands
Setting docstring style simplified

No need for booleans and switches her, setting a style is all.
New commands:

py-set-nil-docstring-style
py-set-pep-257-nn-docstring-style
py-set-pep-257-docstring-style
py-set-django-docstring-style
py-set-symmetric-docstring-style
py-set-onetwo-docstring-style

Removed the following commands

toggle-py-nil-docstring-style
py-nil-docstring-style-on
py-nil-docstring-style-off
toggle-py-onetwo-docstring-style
py-onetwo-docstring-style-on
py-onetwo-docstring-style-off
toggle-py-pep-257-docstring-style
py-pep-257-docstring-style-on
py-pep-257-docstring-style-off
toggle-py-pep-257-nn-docstring-style
py-pep-257-nn-docstring-style-on
py-pep-257-nn-docstring-style-off
toggle-py-symmetric-docstring-style
py-symmetric-docstring-style-on
py-symmetric-docstring-style-off
toggle-py-django-docstring-style
py-django-docstring-style-on
py-django-docstring-style-off
Boolean `py-set-fill-column-p' renamed `py-auto-fill-mode'

which says what it does.

Fill according to `py-docstring-fill-column' and
`py-comment-fill-column'
face of "print", lp:1298328

fixed

With Python3, print-function will get `py-builtins-face',
at Python2 "print" in statement gets `font-lock-keyword-face'