Use SmallVec for VM

[tomoyanonymous]

#11

This PR replaces Vec<T> in the VM and Program codes to SmallVec<[T;4]>.

Sadly, It rather slowers benchmark even in release profile.

No SmallVec

Running benches/bench.rs (/Users/tomoya/codes/mimium-rs/target/release/deps/bench-d4460aba5585daad)

running 4 tests
test tests::bench_multiosc5  ... bench:       1,253 ns/iter (+/- 57)
test tests::bench_multiosc7  ... bench:       1,744 ns/iter (+/- 144)
test tests::bench_multiosc10 ... bench:       2,483 ns/iter (+/- 122)
test tests::bench_multiosc15 ... bench:       3,694 ns/iter (+/- 76)

SmallVec[4] only for vm.rs

Running benches/bench.rs (/Users/tomoya/codes/mimium-rs/target/release/deps/bench-e707ff430debe52f)

running 4 tests
test tests::bench_multiosc5  ... bench:       1,366 ns/iter (+/- 398)
test tests::bench_multiosc7  ... bench:       1,876 ns/iter (+/- 44)
test tests::bench_multiosc10 ... bench:       2,664 ns/iter (+/- 86)
test tests::bench_multiosc15 ... bench:       3,983 ns/iter (+/- 117)

SmallVec[4] vm and program

Running benches/bench.rs (/Users/tomoya/codes/mimium-rs/target/release/deps/bench-e707ff430debe52f)

running 4 tests
test tests::bench_multiosc5  ... bench:       1,545 ns/iter (+/- 111)
test tests::bench_multiosc7  ... bench:       2,140 ns/iter (+/- 147)
test tests::bench_multiosc10 ... bench:       3,036 ns/iter (+/- 85)
test tests::bench_multiosc15 ... bench:       4,541 ns/iter (+/- 106)