Fix: content_title vs. title Mixup for Filters

Signed-off-by: Chris Fiege <chris@tinyhost.de>

flamingo/plugins/title.py

+class Title:
+
+    def contents_parsed(self, context):
+
+        for content in context.contents:
+            if content["content_title"] is not None and content["title"] is None:
+                content["title"] = content["content_title"]
+            elif content["title"] is not None and content["content_title"] is None:
+                content["content_title"] = content["title"]

flamingo/settings.py

@@ -6,6 +6,7 @@ PLUGINS = [
     'flamingo.plugins.rstBootstrap3',
     'flamingo.plugins.rstFile',
     'flamingo.plugins.rstPygments',
+    'plugins/title.py::Title',
 ]
 
 LAYERS = [