[py3] Ported the 'shell' management command.

The user module and the execfile function were removed in Python 3.

Thanks Linovia for the report.
Fixed comment typo
Fixed #18871 - Fixed typo in multi-db docs.
Fixed #18647 - Removed link to Malcolm's blog which is gone.
Replaced some smart_xxx by force_xxx equivalent

smart_str/smart_text should only be used when a potential lazy
string should be preserved in the result of the function call.
Fixed #18751 -- Cleaned up BaseFormSet._should_delete_form

We can do that now that cleaned_data is guaranteed to be
present. Related to [121fd109].
Thanks Simon Charette for his work on the ticket.
Fixed #5725 -- Fixed varchar column size introspection for MySQL

Thanks ferdonline for the initial patch and Karen Tracey for the
related post on django-users.
Made get_table_description also return the size of char fields on SQLite
Fixed #18384 - Reformatted GeoDjango install instructions slightly.
Fixed #18883 -- added a missing self parameter in the docs
Merge pull request #313 from davidfischer/master

Fix comment typo
Merge pull request #311 from gutworth/py3-doc

Indexing bytes is the problem not slicing.
Merge pull request #310 from juanpex/master

fix documentation testing of Selenium WebDriverWait
Fixed #14556 - Documented how to use flatpages in URLconf; thanks Claude Paroz for the draft patch.
Added 1.4.1 and 1.3.2 release notes
Fixed #16309 - Made ModelAdmin.list_filter versionchanged annotations more specific to the sections that changed; thanks akaihola for the suggestion and patch.
Clarify some of the password reset docs

Some of the wording was copied from the change password section. Updated
the text to clarify that the we are talking about password resets.
Fixed #18642 - Added a note suggesting the use of render() rather than render_to_response() if you need RequestContext in your template.
Fixed #16936 - Updated javascript for CSRF protection.

Thanks Idan Gazit for the patch.
Fixed #9920 - Clarfied empty string vs. localhost in settings database host.

Thanks chromano for the draft patch.