Use famhash as generator

If famhash is defined, fetch explicitly that redfam from db and work
only on this

Related Task: [FS#146](https://fs.golderweb.de/index.php?do=details&task_id=146)

bots/markpages.py

@@ -62,6 +62,9 @@ class MarkPagesBot( CurrentPageBot ):  # sets 'current_page' on each treat()
         # Init attribute
         self.__redfams = None  # Will hold a generator with our redfams
 
+        if "famhash" in kwargs:
+            self.famhash = kwargs["famhash"]
+
         # We do not use predefined genFactory as there is no sensefull case to
         # give a generator via cmd-line for this right now
         self.genFactory = pagegenerators.GeneratorFactory()
@@ -102,6 +105,13 @@ class MarkPagesBot( CurrentPageBot ):  # sets 'current_page' on each treat()
             end_after = datetime.strptime(
                 jogobot.config["red.markpages"]["mark_done_after"],
                 "%Y-%m-%d" )
+
+            if hasattr(self, "famhash"):
+                self.__redfams = list(
+                    RedFamWorker.session.query(RedFamWorker).filter(
+                        RedFamWorker.famhash == self.famhash ) )
+
+            else:
                 self.__redfams = list( RedFamWorker.gen_by_status_and_ending(
                     "archived", end_after) )