Expose name, lookups, and command flags from VariableLookup

lib/liquid/variable_lookup.rb

@@ -3,6 +3,8 @@ module Liquid
     SQUARE_BRACKETED = /\A\[(.*)\]\z/m
     COMMAND_METHODS = ['size'.freeze, 'first'.freeze, 'last'.freeze]
 
+    attr_reader :name, :lookups, :command_flags
+
     def self.parse(markup)
       new(markup)
     end