remove unneeded OptionParser separators

lib/rscons/cli.rb

@@ -48,9 +48,6 @@ module Rscons
         OptionParser.new do |opts|
           opts.banner = "Usage: #{$0} [options]"
 
-          opts.separator ""
-          opts.separator "Options:"
-
           opts.on("-f FILE", "Execute FILE (default Rsconsfile)") do |f|
             rsconsfile = f
           end