USe [add]mul_2 (and higher) in mullow_n_basecase.c as in mul_basecase.c.
Add tuning for mulmid code.
Use [add]mul_2 (and higher) in mulshort_n_basecase as in mul_basecase.
Use [add]mul_2 (and higher) in mulmid_basecase as in mul_basecase.
Use GMP's mullo_basecase asm for mullow_n_basecase on x86_64.
Use GMP's mullo_basecase asm for mullow_n_basecase on nehalem.
Use previous archs assembly for Intel's core* CPUs.
Use GMP's mullo_basecase asm for mullow_n_basecase on sandybridge.