Add support for file and image attributes
Handle fuzz data within search facets

TIL Haystack passes "selected_facets" data unfiltered to the search
form, and so you have to be careful in interpretting the data passed.
This change avoids sequence errors when creating a dict from the passed
facet data.
# Last 5 commit messages
# ----------------------
# 07eff7b Add support for file and image attributes [Izidor Matušov]
# ec12c47 Merge pull request #1076 from tangentlabs/issue/1070/offer-prices [David Winterbottom]
# 41c7edc Merge pull request #1020 [David Winterbottom]
# a9eb4f2 Ensure get_discount uses the correct parent charge for discount [David Winterbottom]
# 2de69cc Adjust sample strategies for UK and US [David Winterbottom]
Ensure basket line prices are calculated to correct precision

Use D instead of Decimal everywhere.
Remove dead offers section from product update form

Based on 8617a75, we remove the offers section and correct the loading
of the ranges section within the product dashboard template.
Show spelling suggestion even if no results