This patch changes the interface of netlink-notifier and
rtnetlink-link. Now nln_notifiers are allocated and destroyed by
the module instead of passed in by callers. This allows the
definition of nln_notifier to be hidden, and generally cleans up
the code.
It makes more sense to call nln_notifier_run() and
nln_notifier_wait() simply nln_run() and nln_wait() since they
don't operate on notifiers but the entire nln object. This patch
changes the nln and the rtnetlink-link modules to the new
convention.
This patch renames the rtnetlink module's code to "nln" for
"netlink notifier". Callers are now required to pass in the
netlink protocol to he newly renamed nln_create() function.
Abstracted rtnetlink so that it may be used for messages other than
RTM LINK messages. Created a new rtnetlink-link module which
specifically deals with these kinds of messages and follows the old
rtnetlink API.
