added the_excerpt filter

git-svn-id: https://plugins.svn.wordpress.org/affiliate/trunk@908827 b8457f37-d9ea-0310-8a92-e5e31aec5664
tagged 1.1.0

git-svn-id: https://plugins.svn.wordpress.org/affiliate/trunk@908829 b8457f37-d9ea-0310-8a92-e5e31aec5664