Also introduce a macro to be called by persistent nodes to signal their
persistence during shutdown to hide this mechanism from the node author.
Make node flags have a consistent style in naming.
Document the change.
Thanks to Sam for importing tags in a way that allowed this to be done.
Submitted by: Gleb Smirnoff <glebius@cell.sick.ru>
Also allow the sr and ar drivers to create netgraph versions of their modules.
Document the change to the ksocket node.
The big lines are:
NODEV -> NULL
NOUDEV -> NODEV
udev_t -> dev_t
udev2dev() -> findcdev()
Various minor adjustments including handling of userland access to kernel
space struct cdev etc.
