Refactor with better naming conventions

include/helper.h

include/hnsw.h

include/ipre.hpp

include/sym_field.h

include/sym_field.hpp

include/sym_group.h

include/sym_group.hpp

include/sym_matrix.h

include/sym_matrix.hpp

include/sym_vector.h

include/sym_vector.hpp

src/ipre.cpp

src/sym_field.cpp

src/sym_group.cpp

src/sym_matrix.cpp

src/sym_vector.cpp

tests/CMakeLists.txt

tests/test_group_asym.cpp

tests/test_hnsw.cpp

tests/test_ipre.cpp