- updated API to POST from GET

git-svn-id: https://plugins.svn.wordpress.org/presstrends/trunk@789503 b8457f37-d9ea-0310-8a92-e5e31aec5664
- fixed bug in call

git-svn-id: https://plugins.svn.wordpress.org/presstrends/trunk@789516 b8457f37-d9ea-0310-8a92-e5e31aec5664