- renamed Z -> Int
- made Int ops methods on *Int
- "install" assembly routines dynamically
- replace mulVW functions with mulAddVWW
  of equivalent performance but symmetric functionality
  to divWVW
- implemented scanN

status:
- need mulNN (trivial)
- need division/modulo after which the set of
  elementary operations is complete
- to/from string conversion working

R=rsc
DELTA=320  (124 added, 50 deleted, 146 changed)
OCL=33308
CL=33341