Always output non-localized dates.

See brutasse/#27

This change makes date fields always output RFC-3339 
format dates as the html5 specification requires.
Fixed #43 -- Don't leak variables from widget rendering into the global context.
Updating tox config to test with django's latest minor releases.
Removed a bare except following Django's behaviour

See https://code.djangoproject.com/ticket/17888 for context.
Add a layout example with bootstrap
Fixed typo
Merge pull request #50 from Natim/add_bootstrap_layout_as_an_example

Add a layout example with bootstrap
Add a ImageThumbnailFileInput example
Add a snapshot
Update docs/bootstrap.rst

Fix help_text in bootstrap row file.
Merge pull request #57 from novagile/master

Update documentation
use "current stable" version of openlayers for gis widgets

see http://trac.osgeo.org/openlayers/wiki/HowToDownload
Reuse Django's FILE_INPUT_CONTRADICTION

floppyforms did define its own FILE_INPUT_CONTRADICTION constant. Because of
this combining the Django core field with floppyforms widget would fail
(both use different objects for FILE_INPUT_CONTRADICTION). The import
from Django core fixes this problem.
Pull default date/time formats from settings due to localflavor being removed in Django 1.5.
Keep the previous import for backwards compatibility.
As it turns out, default date/time input formats were removed in Django 1.3 and aren't needed at all.
Merge pull request #59 from dmpayton/master

Django 1.5 removes localflavor
Merge pull request #56 from ddanier/issues/56

floppyforms should import FILE_INPUT_CONTRADICTION instead of defining a new object
Merge pull request #58 from i-trofimtschuk/master

use "current stable" version of openlayers for gis widgets
Merge pull request #51 from Natim/add_image_thumbnail_example

Add a ImageThumbnailFileInput example