added DROP Table statements to delete existing tables
added DROP Table statements to delete existing tables

ohaz/amos-ss15-proj1,ohaz/amos-ss15-proj1,ohaz/amos-ss15-proj1,ohaz/amos-ss15-proj1,ohaz/amos-ss15-proj1,ohaz/amos-ss15-proj1,ohaz/amos-ss15-proj1,ohaz/amos-ss15-proj1