Better error reporting.

* python-django.el:
(python-django-util-shell-command-to-string): New function.
(python-django-util-shell-command-or-error): New function.
(python-django--help-get):
(python-django-info-get-version):
(python-django-info-get-settings):
(python-django-info-get-setting):
(python-django-info-get-app-paths):
(python-django-info-module-path): Use it.
(python-django-open-project): Print user errors to project buffer.
Generate readable code for python interactions
Merge branch 'better-error-handling'