Fix filter states when adding columns

This fixes various issues with filter states when adding columns. We now
maintain multiple states per relay so that we don't lose track of
anything.

Fixes: https://github.com/damus-io/notedeck/issues/431
Fixes: https://github.com/damus-io/notedeck/issues/359
Signed-off-by: William Casarin <jb55@jb55.com>

enostr/src/relay/pool.rs

@@ -22,7 +22,7 @@ impl<'a> PoolEvent<'a> {
     pub fn into_owned(self) -> PoolEventBuf {
         PoolEventBuf {
             relay: self.relay.to_owned(),
-            event: self.event
+            event: self.event,
         }
     }
 }