Add nginx reverse proxy to apache in Vagrant VM

Accessible at port 9001.
Add gunicorn to Vagrant VM
Automatically start dev server in Vagrant VM
Docs: Explain changes to Vagrant VM
Filter by date range in Dasboard/Reporting, if provided
Filter different reports properly
Add reordering products inside ranges
Fix PEP8
Clean range ordering

- Remove forgotten print statement
- Rename `RangeOrdering` to more generic `RangeProduct` (later we can
  add another fields that are not ordering specific)
- Use `display_order` rather than priority (we set the order using
  jQuery sortable, not bump priority of couple products)
Fix backwards incompatible changes
Add correct CSS for date picker

It was using a incomplete bootstrap-datepicker.css. I couldn't find a
better suited replacement, so just switched to an okay looking JQuery UI
theme.

Also switched to the minified version of JQuery UI.
Upgrade timepicker to current version

As part of reviewing datetime pickers, it seemed sensible to bump to the
current version.
Fix custom_range bugs with ugettext_lazy in custom range object name,
and unique fields error when creating existing custom ranges.
Fix for delegate of num_products to a proxy class as documented.
Fix issue with updating basket cookie in the middleware

Handle the case correctly where the basket cookie needs to be deleted
and updated in the same request. This can happen when unfreezing the 
basket. Django's response.delete_cookie doesn't remove the cookie from
request.COOKIES so we need to manually check this.
New lib to get query counts for test suite

nose-django-querycount gives individual and total query counts. This is
helpful to double-check changes that claim to affect query count
(e.g. #1056).
Total query count gives a quick overview, and diff'ing the output for
two different branches works well.
Move timepicker JS load to dashboard's layout.html

@mbertheau correctly suggested as there's dashboard-global
initialisation going on in dashboard.js, loading the timepicker addon
should be global as well. That's more consistent with how we handle
other dashboard plugins as well.
Merge pull request #992 from tangentlabs/issue/992/datetimepicker

Fix datetime picker in dashboard
Remove ancient import

Not sure how this survived this long.
Correct flash message when saving a variant product