Adds @city and @state instance variables, to be populated from search bar

 - default city is cambridge, state ma if params hash is nil
 - otherwise, takes from search bar
 - takes in query, splits based on comma or spaces
 - strips all leading/trailing spacings from each word in the query
 - saves into an array
 - pulls first item in array for city, 2nd in array for state
 - currently only works for US cities and states