Changed Finance API to Google Finance and added Disclaimer

git-svn-id: https://plugins.svn.wordpress.org/show-stock-quotes/trunk@971957 b8457f37-d9ea-0310-8a92-e5e31aec5664
Removed screenshot

git-svn-id: https://plugins.svn.wordpress.org/show-stock-quotes/trunk@971959 b8457f37-d9ea-0310-8a92-e5e31aec5664
Removed screenshot

git-svn-id: https://plugins.svn.wordpress.org/show-stock-quotes/trunk@971960 b8457f37-d9ea-0310-8a92-e5e31aec5664