* ggml: new optimization interface
remove test2.c, test3.c
store adamw params in tensor
move grads from tensor to graph
* avoid segfault upon API misuse
* add ggml-opt.h to public headers
* remove dependence of ggml-opt.cpp on ggml-cpu.h
* use 128 bit loads (i've tried 256->128 to death and its slower)
* double accumulator
* avx bf16 vec dot
* +3% q4_0 inference
* +7% tg +5% pp compared to master
* slower f16c version, kep for reference
* 256b version, also slow. i tried :)
* revert f16
* faster with madd
* split to functions
* Q8_0 and IQ4_NL, 5-7% faster
* fix potential overflow (performance reduced)
* 16 bit add for q4_0 only
* merge
