`BoxedUint` support #135

Job	Run time
clippy	2m 16s
codecov	36s
build-benchmarks	2m 28s
build-wasm (1.73.0, wasm32-unknown-unknown)	21s
build-wasm (stable, wasm32-unknown-unknown)	20s
rustfmt	20s
slow-tests (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	3m 26s
tests (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	48s
slow-tests (x86_64-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	3m 9s
tests (x86_64-unknown-linux-gnu, stable)	33s
	14m 17s

Provide feedback