Fix JavaScript loading bug, update readme, version bump to 0.6.1.

git-svn-id: https://plugins.svn.wordpress.org/inline-google-spreadsheet-viewer/trunk@989690 b8457f37-d9ea-0310-8a92-e5e31aec5664
Rename file for consistent JavaScript naming conventions.

git-svn-id: https://plugins.svn.wordpress.org/inline-google-spreadsheet-viewer/trunk@989692 b8457f37-d9ea-0310-8a92-e5e31aec5664