adding pseudo main method

lib/zoomifier.rb

@@ -1,6 +1,5 @@
 require 'fileutils'
 require 'open-uri'
-require 'rexml/document'
 require 'rubygems'
 require 'rmagick'
 
@@ -173,3 +172,11 @@ module Zoomifier
   end 
   
 end
+
+if __FILE__ == $0
+  if ARGV.length == 1
+    Zoomifier::zoomify(ARGV[0])
+  else
+    puts "Usage: zoomify filename"
+  end
+end