width: 100% is already part of the class.
Remove duplicate classes .table/.striped and exclusivly use the more common one.
Add this class to PostReportReasons/Help, which were missing it.
The wiki page presenter wasn't used, and other_names from wiki page versions
is also unused.
That makes the remaing two implementations functionally the same.
This replaces the old simple versioning helper that existed on
e621. The implementaiton is roughly the same but has been updated
to use newer rails methods.
No, it's not very flexible, but it didn't need to be.
