Add options which display the version of ever2boost

Author: asmsuechan

lib/ever2boost/cli.rb

@@ -25,5 +25,11 @@ def convert(path)
  filename = File.basename(path, '.enex')
  EnexConverter.convert(enex, output_dir, filename)
  end
+
+ map %w[--version -v] => :__print_version
+ desc "--version, -v", "print the version"
+ def __print_version
+ puts Ever2boost::VERSION
+ end
  end
 end