initial work for dynamic swap additions.
don't allocate swap map in allocsys.
emulate old swapon().
header file for new swapon(2)
make this more likely to work; follow naming conventions
new swap(8) program; includes swapon(8) functionality.
garbage collect.
regen.
swapon has a new syscall number; deal with oswapon.
regen.
excise swap from the kernel configuration.  also, finish swapgeneric clean up.
swapconf() is no more.
swap configuration is no longer done at boot time.
cleanup, remote swdevt, some DEBUG -> DIAGNOSTIC
se_name is now an array.
se_name is now an array.  comment swap_off (SWAP_OFF_WORKS).  KNF.  handle swap vp == rootvp
a number of changes:
- remove register.
- add some more debugging.
- some KNF.
- move swap_{ptov,vtop}_addr() up a bit closer to where they are actually used.
- don't add the new swap priority to the priority list until we have actually
  successfully begun swapping on this device.
- if we malloc something, and then fail something else (malloc, or otherwise),
  free what we have malloc()ed.
- disable code allowing root&swap on same device, until it is fully completed.
  assign the vp in the swapdev struct before calling swap_on(), as swap_on()
  wants to use it.  i have absolutely _NO_ idea what was happening before, and
  this is probably the cause of much lossage.  however, things still lose for
  some reason, elsewhere.
remove se_name completely!  solves some of my problems.  thanks to charles for showing me the error of my ways....
some fixes from jason, and some from myself.  disallow non VBLK, as we're
not ready for them (yet?).
clean up a bit.