some of the new fns are only visible internally , to get them visible to the user we
need to put the stuff thats in gmp-impl.h into gmp-h.in and get it to work ,
need to bugger about with configure.in etc 

should addsub return int or limb ?

Test everything for alignment and speed on K10

should the new function be entered in the fat structure?

some of the new fn's are visible to the user , or do we want them internal?

need proper speed tuning for redc_basecase and powm , not the hack that we
have at the mo

for K10 , check tests/try does the different alignments for the shifts

tune params

test on core2

go thru our changes list see what merge did