Search event_* dirs and fix current path order

[wootguy]

../svencoop_event_* dirs should be searched as well. There are unique files there not only replacements. These probably shouldn't be treated as default content since they're only active during events.

Also, the priority ordering is wrong and should be:

1. svencoop_addon
2. svencoop_hd
3. svencoop
4. svencoop_downloads