Remove references to the (missing) categories block. You can find that in habari-extras/common_blocks. Closes habari/habari#546 for master.

It would need to be manually applied to 0.9(.1).
update FlickrSilo for 0.9.2, too
Though publishing a post is an important event in a post's life, it should be minor as there is no change to the content at that point. Making it major just causes weird dates with scheduled posts.
Merge branch '0.9.1' of github.com:habari/system into 0.9.1