Functionality to add tags to post from previous posts

nominous contributed a patch via infocalypse. I only bridged it to the github repos.

Discussion at http://127.0.0.1:8888/Sone/viewPost.html?post=92266106-5575-46ca-9459-2c43ce2468b9 or http://127.0.0.1:8888/Sone/viewPost.html?post=3adba578-793a-4d1c-9aaa-53789c1ef8ab