LNS without tables and using rational maths

[kgrama]

Stable now, 8 and 16bit table/rom less LNS. Performance
Format Roundtrip Add Sub Mul Div
PBF8 28.0 dB 26.1 dB 27.8 dB 20.7 dB 20.4 dB
PBF16 70.7 dB 68.0 dB 69.8 dB 33.3 dB 33.1 dB

Also comes with a fractal demo https://github.com/kgrama/lnscpp