Work on ModelAdmin, summary and searchable fields on classes

Fixes #62, Fixes #103

ProductHolder - removed sort for child pages in ProductList

OrderAddress by member lookup

Created OrderAddress data object for order recording

Order admin

integrate product_id in datafeed

foxy cart controller datafeed, product page summary fields
Merge pull request #123 from jirish/orderAdmin

Work on ModelAdmin, summary and searchable fields on classes