Conversion of https://github.com/ulfjack/ryu to zig.

git clone --recurse-submodules https://github.com/tiehuis/zig-ryu

Requires sh, make, cmake, c++, zig

./build.sh
./bench-reference # reference timing
./bench-zig       # zig timing

• Make more idiomatic
• Add f16 variant
• Add f128 variant (Use partial table set)
• Add specified precision argument (current errol does this after but this is slows things down a fair bit).
• Benchmark against current float printing code (memory consumption/performance).