fake cpuid to test all paths

new function mpn_divexact_byBm1of   generic and x86_64 versions done
done speed, tests
not done try , fat


temporary copy x86_64-defs.m4 in mpn/x86_64 so I can still use .asm files

copy core2/*.asm k10/*.asm to nehalem for a quick boost for that chip

new function divrem_hensel_1 asm and c  , not linked to the system  ie just
a loose file , no test function etc

new functions divrem_euclidean_qr_1 asm and c (qr,r version)  
done try 
not done speed,tests,fat


mpn_divrem_1 with qxn=0 now calls mpn_divrem_euclidean_qr_1 always
replace all internel calls to mpn_divrem_1 with the new euclidean
we could replace mpn_mod_1   as well   !!!