Unsafe API not marked as such

[sdroege]

E.g. the following

libva-rust/src/va.rs

Line 42 in 75f3730

pub fn initialize(native_disp: *mut VANativeDisplay) -> Result<VADisplay, ()> {

The pointer is going to be used internally, and as such the function should be marked unsafe. The user could easily put 123 or anything else in there as raw pointer.