updated screenshots and cleaned up some readme.txt text


git-svn-id: https://plugins.svn.wordpress.org/purple-xmls-google-product-feed-for-woocommerce/trunk@920421 b8457f37-d9ea-0310-8a92-e5e31aec5664
Adding Screenshots

git-svn-id: https://plugins.svn.wordpress.org/purple-xmls-google-product-feed-for-woocommerce/trunk@920422 b8457f37-d9ea-0310-8a92-e5e31aec5664