Get modinfo from Kernel module (.ko)

Example
---

```rust
extern crate modinfo;

fn main() {
    let ko = open("../snd.ko").expect("error: can't open file!");
    println!("{alias:?}", alias = ko.get(b"alias"));
}
```

Rust version compatibility
---

The minimum required Rust version is 1.47.0.

# Contributing

Contributions are very welcome. However, because this library is used widely, and in security-sensitive contexts, all PRs will be carefully scrutinized. Beyond that, this sort of low level library simply needs to be 100% correct. Nobody wants to chase bugs in encoding of any sort.

All this means that it takes me a fair amount of time to review each PR, so it might take quite a while to carve out the free time to give each PR the attention it deserves. I will get to everyone eventually!