Consider fast float-to-ascii and ascii-to-float libraries #2543
Description
Since the API for energy calculators includes converting the coordinates to ASCII and vice versa, we should consider a few options (including MessagePack, compressed JSON, etc.)
Float to ASCII:
https://github.com/vitaut/zmij (nearly 100x faster than sprintf)
ASCII to float:
https://github.com/fastfloat/fast_float (about 6x faster than strtod)
Adding some benchmarks would be helpful