Adjust atom kara_sqr_n crossover.
On nehalem the GMP sqr_basecase is faster. Thus both nehalem and westmere can
use the mpn/x86_64/sqr_basecase.asm file.
Update nehalem tuning values.
Corrected nehalem tuning value.
Merge branch 'master' of https://github.com/wbhart/mpir
update windows builds for GMP sqr_basecase change