Initial fix of attribute ‘target(default)’ is not valid

2nd fix of attribute ‘target(default)’ is not valid

3rd fix by moving pad_parameters into quantizer

Revise Quantizer by adding commoh.hpp

fix typo in default quantizer

Revise FeatVec_T and Quantizer #centroids

revise quantizer train, and some other minor fixes

add some comments on variables

Adding HNSW-QG AVX512f version

add type checker