%task13-1 - Added solution/xml_document.rb
%task13-2 - Used method missing
%task13-2 - Used method missing and put method name in result
%task13-3 - Added to method missing args, but not working .map
%task13-4 - Fixed .map must put result to res
%task13-5 - Formatting result string
%task13-6 - Added &block in method_missing and used yield in body
%task13-7 - Need to fix some troubles with ' '
%task13-8 - Need to add \n when used closed atributes
%task13-9 - Added \n and done