support for filters and little event fix

scripts/base/frameworks/input/main.bro

@@ -11,6 +11,16 @@ export {
 		destination: any;
 		reader: Reader &default=default_reader;
 	};
+
+	type Filter: record {
+		name: string; 
+		## descriptive name. for later removal
+
+
+		pred: function(typ: Input::Event, left: any, right: any): bool &optional;
+		## decision function, that decides if an inserton, update or removal should really be executed
+	};
+		
 }
 
 @load base/input.bif