Add link to detailed instructions for creating Twitter app.


git-svn-id: https://plugins.svn.wordpress.org/tagregator/trunk@778503 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update installation instructions and changelog.


git-svn-id: https://plugins.svn.wordpress.org/tagregator/trunk@778505 b8457f37-d9ea-0310-8a92-e5e31aec5664