Implementing comparison SSE funcs

- `simd4f_getsigns` (`_mm_movemask_ps`), `simd4f_eq` (`_mm_cmpeq_ps`),
`simd4f_lt` (`_mm_cmplt_ps`), `simd4f_gt` (`_mm_cmpgt_ps`), `simd4f_le`
(`_mm_cmple_ps`), `simd4f_ge` (`_mm_cmpge_ps`)