Improvement the README.txt format

git-svn-id: https://plugins.svn.wordpress.org/calculated-fields-form/trunk@1000134 b8457f37-d9ea-0310-8a92-e5e31aec5664
The definitive version.

git-svn-id: https://plugins.svn.wordpress.org/calculated-fields-form/trunk@1000148 b8457f37-d9ea-0310-8a92-e5e31aec5664