device-mapper and libdevmapper ioctl interface

Sorry for the silence I was busy with my GSOC project, but I have really great news for you today. 

I have switched both NetBSD device-mapper and libdevmapper to new ioctl interface which uses property lists library to send/receive information.  Main motivation was 

that old ioctl interface is really messy and hard to maintain, extend and I have had to include GPL licensed file into my driver {dm-ioct.h} and because of it there can be some licensing issues.

New proplib interface is defined in netbsd/netbsd-dm.h file. I have added compat file which translates new proplib dictionary into struct dm_ioctl which is used in all libdevmapper this file is called libdm_netbsd.c .

I have uploaded my code to www.netbsd.org/~haad/dm20080610.tar.bz2 so everybody can review it.