Merge pull request #2611 from daschw/default

Fix `default()`

src/args.jl

@@ -681,11 +681,15 @@ function default(k::Symbol, v)
 end
 
 function default(; kw...)
+    if isempty(kw)
+        reset_defaults()
+    else
         kw = KW(kw)
         RecipesPipeline.preprocess_attributes!(kw)
         for (k,v) in kw
             default(k, v)
         end
+    end
 end
 
 function default(plotattributes::AKW, k::Symbol)