Commit current development

git-svn-id: https://plugins.svn.wordpress.org/wp-to-twitter/trunk@977278 b8457f37-d9ea-0310-8a92-e5e31aec5664
Stable tag 2.9.1; see changelog for full list of changes: Bug fix #author#, AJAX tweet, invalid shortener return, image uploads.

git-svn-id: https://plugins.svn.wordpress.org/wp-to-twitter/trunk@977289 b8457f37-d9ea-0310-8a92-e5e31aec5664