Reverse subsilver2 header nav link locations

so they are consistent with prosilver locations
Add twig comments to link location events

These comments are added to twig location events that are reversed. Sometimes an event named "after" actually renders in a position before, because the event name refers to code location, not rendered placement. This is also inconsistent between subsilver2 and prosilver, so a comment has been added to any files where the actual event selected is not a match for the event file needed.
Merge pull request #27 from VSEphpbb/fixes

Add notes and a fix to the link location event files