Check subgroup permissions with an equal priority so no one subgroup is higher ranked than another.
add recursive permission adding/removing

also other minor fixes
Update plugin.yml
Update Changelog.txt
change ' strip checks
change checkPermissionExists to how Elgarl wants it
fix javadoc
remove excess return false lines since elgarl doesnt like them
Merge pull request #487 from necrodoom/patch-20

add recursive permission adding/removing
Tidy imports
Fix Cyclic mirroring test (silly me)
Change to use LinkedHashSets to preserve ordering.
Fixes an issue with populating bukkit perms in the wrong order.
Fix wildcard negation in parent groups.
Allow Exception permission to override negations when in the same group.
Fix Typo.
Prevent adding sub groups for ranks the granting player doesn't have access to.