compile fix under linux

remove user vector copy to the node, make little faster

Merge pull request spotify#2 from ViperCraft/avx512_testing

AVX512 integration

compile fix

version 1.17.3

fixed issue with empty index and non-zero roots size, align fixes

reduce memory footprint to store packed index.

fixed issued with very tiny index size, synced _make_tree() with upst…

…ream for packedlib

return back packed implementation for Euclidean, more testing

search with filtering by user defined function to speedup scan