CSS fixes for product image handling

The image file field was off 100px to the right, causing the browser to
display the wrong cursor when hovering over it.
Adjust sandbox mod_wsgi config to use less resources
Add Solr config to sandbox
Remove MultiFacetedSearch{View,Form}

These classes have been removed in favour of the new search structure
developed for Oscar's demo site.
Use net_stock_level in search index
Rework faceting

The facets are now fully automatic based on the OSCAR_SEARCH_FACETS
setting.
Rename search form to be more generic
Update release notes with search changes
Ensure search results load products in bulk
Cache is_group per instance

This is a performance improvement as it prevents many SQL queries.  The
is_group property is called several times from within the templates and
this change avoids the dupliate queries.
Facet on product class and rating in sandbox
Fix typo

ProductReview model has property review*er*_name
Fix some typos in the documentation
Remove typos

Fixes #1021
Fix typo and formatting

Fixes #1028
Create a new stacking context for the freakishly large z-index values used in upload-images

Without this, the image form is drawn over a datetimepicker that pops up so
that it overlaps the image form.
Merge branch 'easily-add-new-formset-to-product-update-page' into machtfit

* branch easily-add-new-formset-to-product-update-page:
  Make it trivially easy to add more formsets to the product update page
  Unify __init__ method signature of formset classes
  customize FormSet class after calling inlineformset_factory
  Whitespace, Formatting, PEP8
Merge branch 'origin/issue/1002/pbd_stockrecords' into machtfit

* branch origin/issue/1002/pbd_stockrecords:
  Pre-select partner if appropriate
  Pass user into StockRecordForm
  PBD: Enforce one stock record matching users partners

Force the partner to be the partner of the user when creating and editing stockrecords

Conflicts:
	oscar/apps/dashboard/catalogue/forms.py
	oscar/apps/dashboard/catalogue/views.py
Merge branch 'update-select2-to-3.4.5' into machtfit

* branch update-select2-to-3.4.5:
  Update select2 to version 3.4.5
Merge branch 'origin/issue/856/productimages' into machtfit

* branch origin/issue/856/productimages:
  CSS fixes for product image handling