Possible missing implementations

[fnrizzi]

Some methods seem to be missing in the API:

• sqrt, max and min are missing in simd_common.
• cbrt is missing for vsx and neon
• exp is missing for vsx and neon
• log is implemented only for avx, avx512 and sse and only in case of intel_compiler detected
• copysign and multiplysign are missing for vsx and neon and also in hip_wavefront, cuda, pack, scalar and vector_size