move all trend filters from gatherer to hunter

gatherer/src/trends.rs

@@ -84,18 +84,8 @@ impl TrendAnalyzer {
     }
 
     pub fn process_tag(&mut self, name: &Arc<String>, tag: &Arc<TrendTag>) {
-        if tag.hosts().skip(1).next().is_none() {
-            // ignore spam that is posted by accounts on <1 host
-            return;
-        }
-
         let score = tag.score(self.period, self.until);
 
-        if score <= 0. {
-            // // discard downwards trends
-            return;
-        }
-
         if self.score_threshold.map_or(false, |score_threshold| score < score_threshold) {
             // score is below self.result[..self.size].score
             return;

hunter/src/trend_setter.rs

@@ -123,7 +123,9 @@ async fn run(
     for trend_tag in &trend_tags {
         for (period, scores) in &mut period_scores {
             let score = trend_tag.score(*period, until);
-            scores.push((score, trend_tag));
+            if score > 0. {
+                scores.push((score, trend_tag));
+            }
         }
     }
     // order