Misc. updates to improve debugging, image uploading, up to date user's guide, etc.

git-svn-id: https://plugins.svn.wordpress.org/wp-to-twitter/trunk@1035218 b8457f37-d9ea-0310-8a92-e5e31aec5664
Switch to 2.9.8; misc. bug fixes.

git-svn-id: https://plugins.svn.wordpress.org/wp-to-twitter/trunk@1035220 b8457f37-d9ea-0310-8a92-e5e31aec5664