remove pointless extmon_helper_config in extfile test
Remove 3x unused/pointless plugin callbacks

post_daemonize, pre_privdrop, post_privdrop
Remove full_config plugin callback

(this can now be squished into various other callbacks,
notably load_config(), which is now called for
all loaded plugins even if they didn't have a defined
config hash)
bump plugin API to 14
update plugin API docs
fix scanbuild C99 stuff?

This seems to be necessary on my dev host for some reason...
various NEWS fixups