__on_post__ is not called late enough, does not accurately reflect post.

[petersilva]

when posting v03 in particular, many transformations occur to the message before it gets posted, to the point that post_log isn't much use. It's very misleading because that baseURL and relPath settings, among others are not updated at the time the plugins are called.

[petersilva]

re-arranged to have on_post plugin callbacks called much later, right before the publish.
Changed the name of the publish routine to post... moving the callbacks allowed to remove duplicate code present in both sr_subscribe and sr_post so that it is only present in sr_message.py

now post_log (an on_post plugin) is called after all transformations for v03 have occurred, so the baseURL and relPath, and everything else, is set correctly.

[petersilva]

merged.

[petersilva]

released in 2.19.09