[PATCH] allow to specify node permissions in the rule

[PATCH] allow to specify node permissions in the rule

This allows to set the permissions along with the rule.

This is not a general replacement for the permissions config, but it
may be easier sometimes for the user to specify the permissions along
with the rule, cause the permissions config file wants the final node
name to match, which seems sometimes a bit difficult to guess, if
format % chars are used in the NAME field.

Any value not given in the rule is still be read from the permissions
file or set to the default. This one will also work:

  BUS="usb", KERNEL="video*", NAME="my-%k", OWNER="$local"

A few words to man page are also added and add_perm_dev() is moved into
namedev_parse.c where it belongs to.