Wasm fixes. #77

Job	Run time
nix-fmt-check	21s
nix-flake-check (ubuntu-latest)	29s
nix-flake-check (macos-latest)	4m 15s
cargo (cargo fmt --verbose --all -- --check)	1m 6s
cargo (cargo check --locked --workspace)	3m 27s
cargo (cargo check --locked --examples --workspace)	7m 12s
cargo (cargo test --locked --lib --bins --workspace --features "egui")	6m 51s
cargo (cargo doc --locked --workspace --features "egui")	6m 51s
cargo (cargo test --locked -p nannou_core --no-default-features --features "libm serde")	4m 23s
cargo (cargo build --locked -p nannou --target wasm32-unknown-unknown)	2m 53s
cargo (mdbook build guide/)	6m 26s
cargo (cargo test --locked -p book_tests)	6m 29s
verifications	0s
guide-push-to-deploy	0s
cargo-publish	0s
	50m 43s

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