updating to spree 2.0.0
fixes sql statement but putting quotes around true for compatibility with sqllite
adds attr_accessible for sale_price
brings extension upto date with spree 2.0
brings extension up-to date with spree 2.0. adds helper methods
adds functionality to sale_price can be set via admin
fixes on_sale logic by checking to see if sale_price != original_price
Merge pull request #1 from noorani786/master

Brings extension up-to date with spree 2.0!