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
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.
Adding missing packages to requirements_demo.txt
Added missing datatypes
Fixed offers fixture
previous failed with
'sites/demo/fixtures/offers.json': Cannot set values on a
ManyToManyField which specifies an intermediary model.  Use
offer.RangeProduct's Manager instead.
applies_to_tax_exclusive_prices  has been removed
Bring templatetags inline with earlier renames
commits:
a8a140fa94baa13f778f9a1529de8d5c2b75e3f2
6341b576bf9fa18c4dc1c78aaa88e174826763f6
Added DATACASH_CURRENCY="GBP" to the settings.py
needed by django-oscar-datacash
Extract method that applies the dashboard product list search query
Filter out products the the user isn't allowed to edit in one place

for all affected views. Also make it easy to customize or replace how
products are filtered for non-staff users.
Extract ordering the queryset into a method
Remove now unused method Product.is_user_a_partner_user
Don't hide base class get_queryset.

And get the model object name from the model attribute that
get_object_dict expects to exist anyway. Reason:

class OscarListView(generic.ListView):
    def get_queryset(self):
        ...

class CustomListView(BulkEditMixin, OscarListView):
    # calling get_queryset on this class would resolve to BulkEditMixin.
    # get_queryset and return None.