Refactored code which assembles body argument for wp_remote_post to use array instead of a long string.

git-svn-id: https://plugins.svn.wordpress.org/wpgform/trunk@817460 b8457f37-d9ea-0310-8a92-e5e31aec5664
Prep for v0.63 release.

git-svn-id: https://plugins.svn.wordpress.org/wpgform/trunk@817461 b8457f37-d9ea-0310-8a92-e5e31aec5664