Implement deactivation hook to clear sync schedules.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@992219 b8457f37-d9ea-0310-8a92-e5e31aec5664
Remove unnecessary local variable.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@992222 b8457f37-d9ea-0310-8a92-e5e31aec5664
Display link to crossposted Tumblr entry in metabox.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@992223 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update readme, version bump to 0.7.17.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@992224 b8457f37-d9ea-0310-8a92-e5e31aec5664