Adding version 2.0 with support to Wordpress 4.0 and WooCommerce 2.2 only.

git-svn-id: https://plugins.svn.wordpress.org/woocommerce-custom-currencies/trunk@1013634 b8457f37-d9ea-0310-8a92-e5e31aec5664
Adding beta note

git-svn-id: https://plugins.svn.wordpress.org/woocommerce-custom-currencies/trunk@1013637 b8457f37-d9ea-0310-8a92-e5e31aec5664