several fixes and cleanup

git-svn-id: https://plugins.svn.wordpress.org/woocommerce-invoicexpress/trunk@793005 b8457f37-d9ea-0310-8a92-e5e31aec5664
update changelog

git-svn-id: https://plugins.svn.wordpress.org/woocommerce-invoicexpress/trunk@793007 b8457f37-d9ea-0310-8a92-e5e31aec5664
bump version number

git-svn-id: https://plugins.svn.wordpress.org/woocommerce-invoicexpress/trunk@793009 b8457f37-d9ea-0310-8a92-e5e31aec5664