Set load_kwargs on JSONFormFieldBase instance

The previous fix set load_kwargs on the class itself, so if there are
multiple uses of the class this value gets overwritten.  Moved the code
to set load_kwargs into JSONFieldBase.formfield()
Update README.rst
Update README.rst
Merge pull request #63 from adam-iris/master

Set load_kwargs on JSONFormFieldBase instance
Delete .fields.py.swp
Merge pull request #77 from lambacck/patch-1

Delete .fields.py.swp
attempt to import django.forms.utils rather than django.forms.util
Merge pull request #78 from ngnmnfn/master

attempt to import django.forms.utils rather than django.forms.util
Added better support for python 3
Added test for regex filter
Added new test for saving blank objects
Change subclass of JSONFormField to CharField

This eliminates the problem where Django's model TextField passes parameters to the __init__ of JSONFormField which it can't handle by using a CharField's __init__. This is untested beyond working on my install, I've added no tests.
fix typo in documentation
Merge pull request #84 from diwu1989/patch-1

fix typo in documentation
Setting JSONField as String breaks during South data-migration
Merge pull request #85 from bradyoo/south

Setting JSONField as String breaks during South data-migration
Merge pull request #83 from danostrowski/master

Change subclass of JSONFormField to CharField
Got tests running in Django 1.7
Merge branch 'master' of github.com:bradjasper/django-jsonfield
Added fallback for simplejson