Missing CReprOf impls for u8 and i8

[Timmmm]

The code here seems to be a weirdly incomplete list of types, missing u8, i8 and isize in various places. isize might be tricky I guess but u8 is pretty annoying because it means I can't use Vec<u8> which is surely really common?

This is the error you get with Vec<u8>:

error[E0277]: the trait bound `u8: CReprOf<u8>` is not satisfied
  --> src\lib.rs:19:10
   |
19 | #[derive(CReprOf, AsRust, CDrop)]
   |          ^^^^^^^ the trait `CReprOf<u8>` is not implemented for `u8`
   |
   = help: the following implementations were found:
             <u8 as CReprOf<bool>>
   = note: required because of the requirements on the impl of `CReprOf<Vec<u8>>` for `CArray<u8>`
   = note: required by `c_repr_of`

Unfortunately this is impossible to fix in my code because u8 and CReprOf aren't defined by me.