update to 2.9

Add filter sharing_display_link

Add get_share_title function and filter

Display buttons on CPT archive pages

Adding keyboard accessibility to sharing buttons config page

git-svn-id: https://plugins.svn.wordpress.org/jetpack-sharing/trunk@868350 b8457f37-d9ea-0310-8a92-e5e31aec5664
update changelog in readme

git-svn-id: https://plugins.svn.wordpress.org/jetpack-sharing/trunk@868351 b8457f37-d9ea-0310-8a92-e5e31aec5664
reverse changelog order in readme

git-svn-id: https://plugins.svn.wordpress.org/jetpack-sharing/trunk@868353 b8457f37-d9ea-0310-8a92-e5e31aec5664
minor improvements

git-svn-id: https://plugins.svn.wordpress.org/jetpack-sharing/trunk@869525 b8457f37-d9ea-0310-8a92-e5e31aec5664