Fixed bug present when radio and/or checkbox values contain apostrophe characters.

git-svn-id: https://plugins.svn.wordpress.org/wpgform/trunk@767588 b8457f37-d9ea-0310-8a92-e5e31aec5664
Prep for v0.58 release.

git-svn-id: https://plugins.svn.wordpress.org/wpgform/trunk@767589 b8457f37-d9ea-0310-8a92-e5e31aec5664