Made standings table sortable, added link in table for locations page

-Created helper_method for ‘sortable’ function - leaderboard can now
sort by initials, score, or location
-Added chevron ‘up’/‘down’ glyphicons via bootstrap
-Defined sort and direction functions in standings_controller
-Default sort is on “scores” ascending (will change soon)
-Added links from each location that go to the locations main page - we
still need to link directly to specific locations