Changed the seller-product relationship

Uncommented the seller ForeignKey under Product, and commented out the products field under Seller. Also commented out the seller field from Listing.
Added edit_profile, changed browse_listings
Added urls for search and edit profile
Added back link to product request, edited name
Changed name, products, commented out add listing
Create edit_profile.html
Merge branch 'patch-16' of https://github.com/jlin45/prepay
Merge branch 'patch-17' of https://github.com/jlin45/prepay
Merge branch 'patch-18' of https://github.com/jlin45/prepay
Merge branch 'patch-19' of https://github.com/jlin45/prepay
Merge branch 'patch-20' of https://github.com/jlin45/prepay
merged jennifer's search stuff, and made a few tweaks to get stuff to work.