Rust updates: vec + slice, read_bytes and inner attributes

* The vector mods have been renamed: `std::vec_ng`->`std::vec` and `std::vec`->`std::slice`
* `TcpStream::read_bytes` changed to `TcpStream::read_exact`
* The new syntax for inner attributes have arrived
* The attribute input to the `headers_mod` macro had to be changed. I made a quick fix on that one, which works for the current use.