Feature -- use sessions to persist last search query
Add context for POST to SearchController#update
POST to SearchController#update adds query params to session
GET requests to SearchController#update return results based on session stored query params
Add 'return to search results' path
Fix failing spec

+ For some reason, ActiveRecord is not returning notes in
  reverse order based on id. I had to make similar changes
  to a number of my unit specs. not sure what is going on.
Add 'back to search results' link