Update grappelli/views/related.py

Using standard json library
Fixed inconsistencies in the breadcrumb section of reversion templates, added the missing translation templates tags too
[JS] Removes 3 useless variables.
[JS] Simplifies using .toggle(Boolean).

See http://api.jquery.com/toggle/#toggle-showOrHide.
[JS] Simplifies some $(this).
[JS] Declares a few variables to avoid redundancy.
[JS] Removes useless quotes in Objects.
Merge pull request #297 from nnmware/master

Simplejson deprecated in new version of Django
Merge branch 'master' into stable/2.4.x
updated docs, fixed #300
added hint about static files finders to the docs, see #214
Merge pull request #304 from michelmichel/stable/2.4.x

Fixed inconsistencies in the breadcrumb section of reversion templates, ...
parsing query_string with autocompletes, fixed #308
fixed deprecation warning with urls, see #301, #305, #310
removed dashboard content, fixed #306
Distinct results also in M2M and other related lookups.

Same as 52f9c67.
Merge branch 'stable/2.4.x' of https://github.com/sehmaschine/django-grappelli into stable/2.4.x