ToDo's:

0) configure
- check getrusage in configure, update cputime (auxlib.c)

1) efficiency/memory
- use mpres in step 2
- optimize memory usage in step 2 (use a unique array for multiplies)
- write a mpn version of add3 and duplicate  
- use/implement a mpn_mul_hi_n routine for use in mpn_REDC
- use mpn_addmul_2, mpn_addmul_4 in the basecase REDC [for machines
  where it exists]
- try McLaughlin's algorithm for Montgomery's modular multiplication
  (http://www.ams.org/mcom/0000-000-00/S0025-5718-03-01543-6/home.html)
- consider Colin Percival's generalized DWT for multiplication modulo
  k*a^n+b, where k*a*b is highly composite. May belong to GMP rather than
  GMP-ECM.
- implement assembly code (redc.asm) for other architectures
  (rename it to redc.s, add AM_PROG_AS in configure.in, add an option
	--want_asm or similar)

2) interface
- with -resume, print %time for THIS RUN instead of total run?
	[suggested by SleepHound <sleephound@yahoo.com>]
- when resuming, print the *initial* x0 for P-1/P+1?

