Added error handling for failing to download the Google API due to an invalid key.

git-svn-id: https://plugins.svn.wordpress.org/google-calendar-widget/trunk@1032963 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fixed error accessing invalid data.

git-svn-id: https://plugins.svn.wordpress.org/google-calendar-widget/trunk@1032964 b8457f37-d9ea-0310-8a92-e5e31aec5664