More int type fixes

Just pulled in nightly got a whole bunch of errors like this:
```
error: cannot determine a type for this expression: cannot determine the type of this integer; add a suffix to specify the type explicitly
```

Not sure, may be this just a follow-up on rust-lang/rust#6023?
Why is this signed int? it's getting downcasted to `u8`, so using `u8` should be fine.