Unifyplatform ASM cleanup, speedup

try to unify the UNIX platforms, so we reduce strage errors between them. 
remove some old work-arounds. 
Also, this brings nice vDSP/vecLib speedups (10x and more) to MacOSX, yay! :+1: 
add NTA_ASM flag, to toggle assemply hand-crafted code usage - for debug/same platform/porting..