Fixed broken /trails/ link and moved url tag for navigating to a
specific trail into the <a> tag itself.
- Fixed issue with requesting more panos (wasn't filter out the original
  ones, and original_panos was being used incorrectly)
- Added support for accessing entering a trail by pano number instead of
  id. Currently it just calls Map_ViewTrailById after getting the
  appropriate id. I couldn't seem to get redirect to work correctly.