Don't apply expired filters

Tusker/Filterer.swift

@@ -69,7 +69,7 @@ class Filterer {
         
         matchers = []
         filterObservers = []
-        for filter in filters where filter.contexts.contains(context) {
+        for filter in filters where (filter.expiresAt == nil || filter.expiresAt! > Date()) && filter.contexts.contains(context) {
             guard let matcher = filter.createMatcher() else {
                 continue
             }