Print filenames when logging Markdown formatting.

Because a class can consist of several files, list all the files
separated by spaces.

Author: nene

lib/jsduck/app.rb

@@ -165,14 +165,15 @@ def format_classes
       class_formatter.include_types = !@opts.export
       # Format all doc-objects in parallel
       formatted_classes = @parallel.map(@relations.classes) do |cls|
-        Logger.instance.log("Markdown formatting #{cls[:name]}")
+        files = cls[:files].map {|f| f[:filename] }.join(" ")
+        Logger.instance.log("Markdown formatting #{cls[:name]}", files)
         begin
           {
             :doc => class_formatter.format(cls.internal_doc),
             :images => doc_formatter.images
           }
         rescue
-          Logger.instance.fatal("Error while formatting #{cls[:name]}", $!)
+          Logger.instance.fatal("Error while formatting #{cls[:name]} #{files}", $!)
           exit(1)
         end
       end