fixed problems with inserting duplicate answers

git-svn-id: https://plugins.svn.wordpress.org/chained-quiz/trunk@962298 b8457f37-d9ea-0310-8a92-e5e31aec5664
new version number to reflect the previous change and force update

git-svn-id: https://plugins.svn.wordpress.org/chained-quiz/trunk@962299 b8457f37-d9ea-0310-8a92-e5e31aec5664