Added a loop to include placeholder values for multiple value columns

git-svn-id: https://plugins.svn.wordpress.org/simple-retail-menus/trunk@875153 b8457f37-d9ea-0310-8a92-e5e31aec5664
Including upadted 4.2 main file and readme file.

git-svn-id: https://plugins.svn.wordpress.org/simple-retail-menus/trunk@875155 b8457f37-d9ea-0310-8a92-e5e31aec5664