made delete button hidden until mouseover
uploaded delete button png
create a route for searching
removed unecessary `@student` variable
fixed delete by index; added autolinking hashtags
- delete function not deleting the correct note due to $index grabbing
  the post-sort order; function now grbas the item and controller
determine correct index with `indexOf`
- added function in student that will replace hashtags with links to the
  search url for that tag