Documentation updates.

Logger.pm

@@ -191,7 +191,7 @@ sub init_database_log {
 # @endverbatim
 #
 # @param type The log event type, may be any string up to 64 characters long.
-# @param user The ID of the user to log as the event triggerer.
+# @param user The ID of the user to log as the event triggerer, use 0 for unknown/internal.
 # @param ip   The IP address of the user, defaults to "unknown" if not supplied.
 # @param data The event data, may be any string up to 255 characters.
 sub log {

System.pm

@@ -76,7 +76,8 @@ sub init {
 ## @method void clear()
 # Delete all references to other application objects from this System object. This
 # must be called before the program closes to prevent circular references messing
-# with cleanup.
+# with cleanup. Subclasses may wish to override this to explicitly break any
+# circular references created during init().
 sub clear {
     my $self = shift;