Make legend transparent.

apachedex/__init__.py

@@ -245,10 +245,12 @@ def graphPair(daily_data, date_format, graph_period, apdex_y_min=None,
       'grid': {
         'hoverable': True,
       },
+      'legend': {
+        'backgroundOpacity': 0.25,
+      },
     },
   )
 
-
 def graph(title, data, options={}):
   result = []
   append = result.append