Update links to new name.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@848628 b8457f37-d9ea-0310-8a92-e5e31aec5664
Always save the Tumblr host basename. It's, um, important. :)

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@848629 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update README with screenshots.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@848631 b8457f37-d9ea-0310-8a92-e5e31aec5664