This adds a hook_user_config for plugins designed to return per-user
configuration directives. Qpsmtpd::Address::config() triggers a
hook_user_config plugin.
The patch below fixes many errors of the form:
*** WARNING: line containing nothing but whitespace in paragraph at line 37 in file writing.pod
*** WARNING: line containing nothing but whitespace in paragraph at line 40 in file writing.pod
There are also a couple of minor typo-fixes.
While writing a plugin for our new spamfilter implementation I noticed
some minor error in the documentation. From the documentation it
sounds like the hook_ok and hook_deny hooks get the previous hook as
parameter.. The truth is: it is the previous plugin.
