Added bench for camel case
Added bench for camel case

BENCHMARK RESULTS:

```
test cases::camelcase::tests::bench_camel                  ... bench:       1,771 ns/iter (+/- 188)
test cases::camelcase::tests::bench_camel_from_sname       ... bench:       1,187 ns/iter (+/- 355)
test cases::camelcase::tests::bench_is_camel               ... bench:      49,600 ns/iter (+/- 9,704)
```

whatisinternet/Inflector